PT - JOURNAL ARTICLE AU - Sears, Paul B. TI - VEGETATION MAPPING AID - 10.1126/science.53.1371.325 DP - 1921 Apr 08 TA - Science PG - 325--327 VI - 53 IP - 1371 4099 - http://science.sciencemag.org/content/53/1371/325.short 4100 - http://science.sciencemag.org/content/53/1371/325.full SO - Science1921 Apr 08; 53