TY - BK ED - World Congress of Soil Science, 15 TI - Commission IV: Symposia SN - 968-6201-23-8 U1 - 631.4 PY - 1994/// CY - Acapulco, Gro. (Mexico) PB - International Society of Soil Science|Mexican Society of Soil Science|INEGI, N1 - v. 5a ER -