共 72 条
[1]
BEAN LH, 1966, FAO6 WHOFAOUNICEF PR, P20
[2]
BLAKELY BD, 1974, GRASSLANDS US THEIR, P6
[3]
Borgstrom G., 1973, Ambio, V2, P214
[4]
BRUNTHAVER CG, 1974, JAN AM FARM BUR FED
[5]
CLAWSON M, 1963, LAND AM TRENDS PROSP
[6]
COCHRANE W, 1974, FEAST FAMINE UNCERTA
[7]
CULVER DW, 1973, 1973 NAT AGR OUTL C
[8]
DOVRING F, 1974, SCI AM, V230, P15
[9]
FENTON TE, 1971, 66 IOW AGR HOM EC EX
[10]
FREY K J, 1973, P9