International Journal of Wildland Fire International Journal of Wildland Fire Society
Journal of the International Association of Wildland Fire
RESEARCH ARTICLE

Fire intensity, fire severity and burn severity: a brief review and suggested usage

Jon E. Keeley

A US Geological Survey, Western Ecological Research Center, Sequoia – Kings Canyon Field Station, 47050 Generals Highway, Three Rivers, CA 93271, USA.

B Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA. Email: jon_keeley@usgs.gov

International Journal of Wildland Fire 18(1) 116-126 http://dx.doi.org/10.1071/WF07049
Submitted: 15 March 2007  Accepted: 15 April 2008   Published: 17 February 2009

Abstract

Several recent papers have suggested replacing the terminology of fire intensity and fire severity. Part of the problem with fire intensity is that it is sometimes used incorrectly to describe fire effects, when in fact it is justifiably restricted to measures of energy output. Increasingly, the term has created confusion because some authors have restricted its usage to a single measure of energy output referred to as fireline intensity. This metric is most useful in understanding fire behavior in forests, but is too narrow to fully capture the multitude of ways fire energy affects ecosystems. Fire intensity represents the energy released during various phases of a fire, and different metrics such as reaction intensity, fireline intensity, temperature, heating duration and radiant energy are useful for different purposes. Fire severity, and the related term burn severity, have created considerable confusion because of recent changes in their usage. Some authors have justified this by contending that fire severity is defined broadly as ecosystem impacts from fire and thus is open to individual interpretation. However, empirical studies have defined fire severity operationally as the loss of or change in organic matter aboveground and belowground, although the precise metric varies with management needs. Confusion arises because fire or burn severity is sometimes defined so that it also includes ecosystem responses. Ecosystem responses include soil erosion, vegetation regeneration, restoration of community structure, faunal recolonization, and a plethora of related response variables. Although some ecosystem responses are correlated with measures of fire or burn severity, many important ecosystem processes have either not been demonstrated to be predicted by severity indices or have been shown in some vegetation types to be unrelated to severity. This is a critical issue because fire or burn severity are readily measurable parameters, both on the ground and with remote sensing, yet ecosystem responses are of most interest to resource managers.

Additional keywords: BAER, dNBR Landsat Thematic Mapper, soil burn severity.


References

Alexander ME1982Calculating and interpreting forest fire intensities.Canadian Journal of Botany60349357

Andrews PL, Rothermel RC (1982) Charts for interpreting wildland fire behavior characteristics. USDA Forest Service, Intermountain Forest and Range Experiment Station, General Technical Report INT-131. (Ogden, UT)

Auld TDO’Connell MA1991Predicting patterns of post-fire germination in 25 eastern Australian Fabaceae.Australian Journal of Ecology165370
doi:10.1111/J.1442-9993.1991.TB01481.X

Beadle NCW1940Soil temperatures during forest fires and their effect on the survival of vegetation.Journal of Ecology28180192doi:10.2307/2256168

Bobbe T, Finco MV, Quayle B, Lannom K, Sohlberg R, Parsons A (2004) Field measurements for the training and validation of burn severity maps from spaceborne, remotely sensed imagery. Joint Fire Science Program. (Boise, ID) Available at http://jfsp.nifc.gov/news/doc/highlight5-04.pdf [Verified 21 December 2008]

Bond WJ, van Wilgen BW (1996) ‘Fire and Plants.’ (Chapman & Hall: New York)

Bradstock RAAuld TD1995Soil temperatures during experimental bushfires in relation to fire intensity: consequences for legume germination and fire management in south-eastern Australia.Journal of Applied Ecology327684doi:10.2307/2404417

Brewer KCWinne JCRedmond RLOpitz DWMangrich MV2005Classifying and mapping wildfire severity: a comparison of methods.Photogrammetric Engineering and Remote Sensing713111320

Brooks ML2002Peak fire temperatures and effects on annual plants in the Mojave Desert.Ecological Applications1210881102
doi:10.1890/1051-0761(2002)012[1088:PFTAEO]2.0.CO;2

Buckley AJ (1993) Fuel reducing regrowth forests with a wiregrass fuel type: fire behaviour guide and prescriptions. Department of Conservation and Environment, Research Report No. 40. (Melbourne)

Burrows ND1995A framework for assessing acute impacts of fire in jarrah forests for ecological studies.CALM Science4Suppl.5966

Byram GM (1959) Combustion of forest fuels. In ‘Forest Fire: Control and Use’. (Ed. KP Davis) pp. 61–89. (McGraw-Hill: New York)

Cannon SHKirkham RMParise M2001Wildfire-related debris-flow initiation processes, Storm King Mountain, Colorado.Geomorphology39171188
doi:10.1016/S0169-555X(00)00108-2

Catchpole W (2000) The international scene and its impact on Australia. In ‘National Academies Forum Proceedings of the 1999 Seminar: Fire! The Australian Experience’, 30 September–1 October 1999, University of Adelaide, Australia. pp. 137–148. Australian Academy of Technological Sciences and Engineering Limited. (National Academies Forum: Canberra, ACT)

Catchpole EACatchpole WRRothermel RC1993Fire behavior experiments in mixed fuel complexes.International Journal of Wildland Fire34557doi:10.1071/WF9930045

Chafer CJNoonan MMcnaught E2004The post-fire measurement of fire severity and intensity in the Christmas 2001 Sydney wildfires.International Journal of Wildland Fire13227240doi:10.1071/WF03041

Chappell CBAgee JK1996Fire severity and tree seedling establishment in Abies magnifica forests, southern Cascades, Oregon.Ecological Applications6628640doi:10.2307/2269397

Chatto K, Tolhurst KG (2004) A review of the relationship between fireline intensity and the ecological and economic effects of fire, and methods currently used to collect fire data. Department of Sustainability and Environment, Fire Management Branch, Research Report No. 67. (Melbourne)

Cheney P1990Quantifying bushfires.Mathematical and Computer Modelling13915doi:10.1016/0895-7177(90)90094-4

Chuvieco ERiano DDanson FMMartin P2006Use of a radiative transfer model to simulate the post-fire spectral response to burn severity.Journal of Geophysical Research111G04S09.doi:10.1029/2005JG000143

Cocke AEFule PZCrouse JE2005Comparison of burn severity assessments using Differenced Normalized Burn Ratio and ground data.International Journal of Wildland Fire14189198doi:10.1071/WF04010

Conard SGSukhinin AIStocks BJCahoon DRDavidenko EPIvanova GA2002Determining effects of area burned and fire severity on carbon cycling and emissions in Siberia.Climatic Change55197211doi:10.1023/A:1020207710195

Cram DS, Baker TT, Boren J (2006) Wildland fire effects in silviculturally treated vs. untreated stands of New Mexico and Arizona. USDS Forest Service, Rocky Mountain Research Station, Research Paper RMRS-RP-55. (Fort Collins, CO)

DeBano LF2000Water repellency in soils: a historical overview.Journal of Hydrology231–232432doi:10.1016/S0022-1694(00)00180-3

Dennison PECharoensiri KRoberts DAPeterson SHGreen RO2006Wildfire temperature and land cover modeling using hyperspectral data.Remote Sensing of Environment100212222doi:10.1016/J.RSE.2005.10.007

Dickinson MB, Johnson EA (2001) Fire effects on trees. In ‘Forest Fires: Behavior and Ecological Effects’. (Eds EA Johnson, K Miyanishi) pp. 477–525. (Academic Press: San Francisco, CA)

Doerr SHShakesby RABlake WHChafer CJHumphreys GSWallbrink PJ2006Effects of differing wildfire severities on soil wettability and implications for hydrological response.Journal of Hydrology319295311doi:10.1016/J.JHYDROL.2005.06.038

Epting JVerbyla DSorbel B2005Evaluation of remotely sensed indices for assessing burn severity in interior Alaska using Landsat TM and ETM+.Remote Sensing of Environment96328339doi:10.1016/J.RSE.2005.03.002

Fernandes PMCatchpole WRRego FC2000Shrubland fire behaviour modelling with microplot data.Canadian Journal of Forest Research30889899doi:10.1139/CJFR-30-6-889

Finney MAMartin RE1992Calibration and field testing of passive flame height sensors.International Journal of Wildland Fire2115122doi:10.1071/WF9920115

Flinn MAWein RW1977Depth of underground plant organs and theoretical survival during fire.Canadian Journal of Botany5525502554doi:10.1139/B77-291

Gill AMAshton DH1968The role of bark type in relative tolerance to fire of three Central Victorian eucalypts.Australian Journal of Botany16491498doi:10.1071/BT9680491

González-Pelayo OAndreu VCampo JGimeno-García ERubio JL2006Hydrological properties of a Mediterranean soil burned with different fire intensities.Catena68186193doi:10.1016/J.CATENA.2006.04.006

Hammill KABradstock RA2006Remote sensing of fire severity in the Blue Mountains: influence of vegetation type and inferring fire intensity.International Journal of Wildland Fire15213226doi:10.1071/WF05051

Hartford RAFrandsen WH1992When it’s hot, it’s hot... or maybe it’s not! (Surface flaming may not portend extensive soil heating).International Journal of Wildland Fire2139144doi:10.1071/WF9920139

Hirsch KGMartell DL1996A review of initial attack fire crew productivity and effectiveness.International Journal of Wildland Fire6199215doi:10.1071/WF9960199

Hubbert KRPreisler HKWohlgemuth PMGraham RCNarog MG2006Prescribed burning effects on soil physical properties and soil water repellency in a steep chaparral watershed, southern California, USA.Geoderma130284298doi:10.1016/J.GEODERMA.2005.02.001

Ice GGNeary DGAdams PW2004Effects of wildfire on soils and watershed processes.Journal of Forestry1021620

Jain TPilliod DGraham R2004Tongue-tied.Wildfire42236


Johnson EA (1992) ‘Fire and Vegetation Dynamics: Studies from the North American Boreal Forest.’ (Cambridge University Press: Cambridge, UK)

Johnson EA, Miyanishi K (2001) Strengthening fire ecology’s roots. In ‘Forest Fires: Behavior and Ecological Effects’. (Eds EA Johnson, K Miyanishi) pp. 1–9. (Academic Press: San Diego, CA)

Johnstone JFChapin FSIII2006Effects of soil burn severity on post-fire tree recruitment in boreal forest.Ecosystems91431
doi:10.1007/S10021-004-0042-X

Keeley JE (1981) Reproductive cycles and fire regimes. In ‘Proceedings of the Conference Fire Regimes and Ecosystem Properties’, 11–15 December 1978, Honolulu, HI. (Eds HA Mooney, TM Bonnicksen, NL Christensen, JE Lotan, WA Reiners) USDA Forest Service, General Technical Report WO-26, pp. 231–277. (Washington, DC)

Keeley JE2006aFire severity and plant age in post-fire resprouting of woody plants in sage scrub and chaparral.Madrono53373379doi:10.3120/0024-9637(2006)53[373:FSAPAI]2.0.CO;2

Keeley JE2006bFire management impacts on invasive plant species in the western United States.Conservation Biology20375384doi:10.1111/J.1523-1739.2006.00339.X

Keeley JEMcGinnis T2007Impact of prescribed fire and other factors on cheatgrass persistence in a Sierra Nevada ponderosa pine forest.International Journal of Wildland Fire1696106doi:10.1071/WF06052

Keeley JEFotheringham CJBaer-Keeley M2005Determinants of post-fire recovery and succession in Mediterranean-climate shrublands of California.Ecological Applications1515151534doi:10.1890/04-1005

Keeley JEBrennan TPfaff AH2008Fire severity and ecosystem responses following crown fires in California shrublands.Ecological Applications1815301546doi:10.1890/07-0836.1

Key CH, Benson NC (2006) Landscape Assessment (LA). In ‘FIREMON: Fire Effects Monitoring and Inventory System’. (Eds DC Lutes, RE Keane, JF Caratti, CH Key, NC Benson, S Sutherland, LJ Gangi) USDA Forest Service, Rocky Mountain Research Station, General Technical Report RMRS-GTR-164-CD, p. LA-1-55. (Fort Collins, CO)

Kokaly RFRockwell BWHaire SLKing TVV2007Characterization of post-fire surface cover, soils, and burn severity at the Cerro Grande Fire, New Mexico, using hyperspectral and multispectral remote sensing.Remote Sensing of Environment106305325doi:10.1016/J.RSE.2006.08.006

Larson AJFranklin JF2005Patterns of conifer tree regeneration following an autumn wildfire event in the western Oregon Cascade Range, USA.Forest Ecology and Management2182536doi:10.1016/J.FORECO.2005.07.015

Lecomte NSimard MFenton NBergeron Y2006Fire severity and long-term ecosystem biomass dynamics in coniferous boreal forests of eastern Canada.Ecosystems912151230doi:10.1007/S10021-004-0168-X

Lentile LBHolden ZASmith AMSFalkowski MJHudak ATMorgan PLewis SAGessler PEBenson NC2006Remote sensing techniques to assess active fire characteristics and post-fire effects.International Journal of Wildland Fire15319345doi:10.1071/WF05097

Lewis SAWu JQRobichaud PR2006Assessing burn severity and comparing soil water repellency, Hayman Fire, Colorado.Hydrological Processes20116doi:10.1002/HYP.5880

Ludwig JABastin GNWallace JFMcVicar TR2007Assessing landscape health by scaling with remote sensing: when is it not enough?Landscape Ecology22163169doi:10.1007/S10980-006-9038-6

McCaw WLSmith RHNeal JE1997Prescribed burning of thinning slash in regrowth stands of karri (Eucalyptus diversicolor). 1. Fire characteristics, fuel consumption and tree damage.International Journal of Wildland Fire72940doi:10.1071/WF9970029

Mercer GNGill AMWeber RO1994A time-dependent model of fire impact on seed survival in woody fruits.Australian Journal of Botany427181doi:10.1071/BT9940071

Michaletz STJohnson EA2003Fire and biological processes.Journal of Vegetation Science14622623doi:10.1658/1100-9233(2003)014[0622:BR]2.0.CO;2

Miller JDYool SR2002Mapping forest post-fire canopy consumption in several overstory types using multi-temporal Landsat TM and ETM data.Remote Sensing of Environment82481496doi:10.1016/S0034-4257(02)00071-8

Miyanishi K (2001) Duff consumption. In ‘Forest Fires: Behavior and Ecological Effects’. (Eds EA Johnson, K Miyanishi) pp. 437–475. (Academic Press: San Francisco, CA)

Moody JAMartin PA2001Initial hydrologic and geomorphic response following a wildfire in the Colorado front range.Earth Surface Processes and Landforms2610491070doi:10.1002/ESP.253

Moreno JMOechel WC1989A simple method for estimating fire intensity after a burn in California chaparral.Acta Oecologica105768

Nearing MAJetten VBaffaut CCerda OCouturier AHernandez MLe Bissonnais YNichols MHNunes JPRenschler CSSouchère Vvan Oost K2005Modeling response of soil erosion and runoff to changes in precipitation and cover.Catena61131154
doi:10.1016/J.CATENA.2005.03.007

Neary DGKlopatek CCDeBano LFFfolliott PF1999Fire effects on belowground sustainability: a review and synthesis.Forest Ecology and Management1225171doi:10.1016/S0378-1127(99)00032-8

Nelson RMJrAdkins CW1986Flame characteristics of wind-driven surface fires.Canadian Journal of Forest Research1612931300doi:10.1139/X86-229

NWCG (2006) Glossary of wildland fire terminology. National Wildfire Coordinating Group, Incident Operations Standards Working Team. Available at http://www.nwcg.gov/pms/pubs/glossary/index.htm [Verified 21 December 2008]

Parsons A (2003) Burned Area Emergency Rehabilitation (BAER) soil burn severity definitions and mapping guidelines. Draft. USDA Forest Service, Rocky Mountain Research Station. (Missoula, MT) Available at http://www.fws.gov/fire/ifcc/esr/Remote%20Sensing/soil_burnsev_summary_guide042203.pdf [Verified 21 December 2008]

Perez BMoreno JM1998Methods for quantifying fire severity in shrubland-fires.Plant Ecology13991101doi:10.1023/A:1009702520958

Pérez-Cabello FFernández JRLlovería RMGarcía-Martín A2006Mapping erosion-sensitive areas after wildfires using fieldwork, remote sensing, and geographic information systems techniques on a regional scale.Journal of Geophysical Research – Biogeosciences111G04S10.doi:10.1029/2005JG000148

Peterson DLRyan KC1986Modeling post-fire conifer mortality for long-range planning.Environmental Management10797808doi:10.1007/BF01867732

Robichaud PR2000Fire effects on infiltration rates after prescribed fire in Northern Rocky Mountain forests, USA.Journal of Hydrology231–232220229doi:10.1016/S0022-1694(00)00196-7

Robichaud PR, Beyers JL, Neary DG (2000) Evaluating the effectiveness of post-fire rehabilitation treatments. USDA Forest Service, Rocky Mountain Research Station, General Technical Report RMRS-GTR-63. (Ogden, UT)

Robichaud PR, Elliot WJ, Pierson FB, Hall DE, Moffet CA, Ashmum LF (2007a) Erosion Risk Management Tool (ERMiT) user manual (version 2006.01.18). USDA Forest Service, Rocky Mountain Research Station, General Technical Report RMRS-GTR-188. (Ogden, UT)

Robichaud PRLewis SALaes DYMHudak ATKodaly RFZamudio JA2007bPost-fire soil burn severity mapping with hyperspectral image unmixing.Remote Sensing of Environment1084467480doi:10.1016/J.RSE.2006.11.027

Rogan JFranklin J2001Mapping wildfire burn severity in southern California forests and shrublands using Enhanced Thematic Mapper imagery.Geocarto International16491106doi:10.1080/10106040108542218

Roldán-Zamarrón AMerino-de-Miguel SGonzález-Alonso FGarcía-Gigorro SCuevas JM2006Minas de Riotinto (south Spain) forest fire: Burned area assessment and fire severity mapping using Landsat 5-TM, Envisat-MERIS, and Terra-Modis post-fire images.Journal of Geophysical Research – Biogeosciences111G04S11.doi:10.1029/2005JG000136

Rothermel RC (1972) A mathematical model for predicting fire spread in wildland fuels. USDA Forest Service, Intermountain Forest and Range Experiment Station, Research Paper INT-115. (Ogden, UT)

Roy DPBoschetti LTrigg SN2006Remote sensing of fire severity: assessing the performance of the Normalized Burn Ratio.IEEE Geoscience and Remote Sensing Letters3112116doi:10.1109/LGRS.2005.858485

Ruiz-Gallardo JRCastano SCalera A2004Application of remote sensing and GIS to locate priority intervention areas after wildland fires in Mediterranean systems: a case study from south-eastern Spain.International Journal of Wildland Fire13241252doi:10.1071/WF02057

Ryan KC (1981) Evaluation of a passive flame-height sensor to estimate forest fire intensity. USDA Forest Service, Pacific Northwest Forest and Range Experiment Station, Research Note PNW-390. (Portland, OR)

Ryan KC2002Dynamic interactions between forest structure and fire behavior in boreal ecosystems.Silva Fennica361339

Ryan KCFrandsen WH1991Basal injury from smoldering fires in mature Pinus ponderosa Laws.International Journal of Wildland Fire1107118
doi:10.1071/WF9910107

Ryan KC, Noste NV (1985) Evaluating prescribed fires. In ‘Proceedings, Symposium and Workshop on Wilderness Fire’, 15–18 November 1983, Missoula, MT. (Eds JE Lotan, BM Kilgore, WC Fischer, RW Mutch) USDA Forest Service, Intermountain Forest and Range Experiment Station, General Technical Report INT-182, pp. 230–238. (Missoula, MT)

Sackett SS, Haase SM, Harrington MG (1996) Lessons learned from fire use restoring south-western ponderosa pine ecosystems. In ‘Conference on Adaptive Ecosystem Restoration and Management: Restoration of Cordilleran Conifer Landscapes of North America’, 6–8 June 1995, Flagstaff, AZ. (Eds WW Covington, PK Wagner) USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, General Technical Report RM-GTR-278, pp. 54–61. (Fort Collins, CO)

Salazar LABradshaw LS1986Display and interpretation of fire behavior probabilities for long-term planning.Environmental Management10393402doi:10.1007/BF01867265

Scott JH, Reinhardt ED (2001) Assessing crown fire potential by linking models of surface and crown fire behavior. USDA Forest Service, Rocky Mountain Research Station, Research Paper RMRS-RP-29. (Fort Collins, CO)

Simard AJ1991Fire severity, changing scales, and how things hang together.International Journal of Wildland Fire12334doi:10.1071/WF9910023

Smith AMSWooster MJDrake NADipotso FMFalkowski MJHudak AT2005Testing the potential of multi-spectral remote sensing for retrospectively estimating fire severity in African savannahs.Remote Sensing of Environment9792115doi:10.1016/J.RSE.2005.04.014

Stronach NHMcNaughton SJ1989Grassland fire dynamics in the Serengeti ecosystem, and a potential method of retrospectively estimating fire energy.Journal of Applied Ecology2610251033doi:10.2307/2403709

Sugihara NG, van Wagtendonk JW, Fites-Kaufman J (2006) Fire as an ecological process. In ‘Fire in California’s Ecosystems’. (Eds NG Sugihara, JW van Wagtendonk, KE Shaffer, J Fites-Kaufman, AE Thode) pp. 58–74. (University of California: Los Angeles, CA)

Tolhurst KG1995Fire from a flora, fauna and soil perspective: sensible heat measurement.CALM Science4Suppl.4588

Turner MGHargrove WWGardner RHRomme WH1994Effects of fire on landscape heterogeneity in Yellowstone National Park, Wyoming.Journal of Vegetation Science5731742
doi:10.2307/3235886

Turner MGRomme WHGardner RH1999Pre-fire heterogeneity, fire severity, and early post-fire plant reestablishment in subalpine forests of Yellowstone National Park, Wyoming.International Journal of Wildland Fire92136doi:10.1071/WF99003

Valette J-CGomendy VMarechal JHoussard CGillon D1994Heat transfer in the soil during very low-intensity experimental fires: the role of duff and soil moisture content.International Journal of Wildland Fire4225237doi:10.1071/WF9940225

van Wagner CE1973Height of crown scorch in forest fires.Canadian Journal of Forest Research3373378doi:10.1139/X73-055

van Wagtendonk JWRoot RRKey CH2004Comparison of AVIRIS and Landsat ETM+ detection capabilities for burn severity.Remote Sensing of Environment92397408doi:10.1016/J.RSE.2003.12.015

Vesk PAWestoby M2004Sprouting ability across diverse disturbances and vegetation types worldwide.Journal of Ecology92310320doi:10.1111/J.0022-0477.2004.00871.X

Wade DD1993Thinning young loblolly pine stands with fire.International Journal of Wildland Fire3169178doi:10.1071/WF9930169

Wang GG, Kemball KJ (2003) The effect of fire severity on early development of understory vegetation following a stand-replacing wildfire. In ‘5th Symposium on Fire and Forest Meteorology jointly with 2nd International Wildland Fire Ecology and Fire Management Congress’, 16–20 November 2003, Orlando, FL. (American Meteorological Society: Boston, MA)

Weber RO (2001) Wildland fire spread models. In ‘Forest Fires: Behavior and Ecological Effects’. (Eds EA Johnson, K Miyanishi) pp. 151–169. (Academic Press: San Diego, CA)

Wells CG, DeBano LF, Lewis CE, Fredriksen RL, Franklin EC, Froelich RC, Dunn PH (1979) Effects of fire on soil. A state-of-knowledge review. USDA Forest Service, General Technical Report WO-7. (Washington, DC)

Whelan RJ (1995) ‘The Ecology of Fire.’ (Cambridge University Press: Cambridge, UK)

White JDRyan KCKey CCRunning SW1996Remote sensing of forest fire severity and vegetation recovery.International Journal of Wildland Fire6125136doi:10.1071/WF9960125

White PS, Pickett STA (1985) Natural disturbance and patch dynamics: an introduction. In ‘The Ecology of Natural Disturbance and Patch Dynamics’. (Eds STA Pickett, PS White) pp. 1–13. (Academic Press: San Diego, CA)

Williams RJGill AMMoore PHR1998Seasonal changes in fire behaviour in a tropical savanna in northern Australia.International Journal of Wildland Fire8227239doi:10.1071/WF9980227

Wilson CJCarey JWBeeson PCGard MOLane LJ2001A GIS-based hillslope erosion and sediment delivery model and its application in the Cerro Grande burn area.Hydrological Processes1529953010doi:10.1002/HYP.387

Wooster MJZhukov BOertel D2003Fire radiative energy for quantitative study of biomass burning: derivation from the BIRD experimental satellite and comparison to MODIS fire products.Remote Sensing of Environment8683107doi:10.1016/S0034-4257(03)00070-1



Export Citation Cited By (368)