共 27 条
[2]
Behrens W.W., 1972, N Y
[3]
Beyers R.J., 1964, AM BIOL TEACH, V26, P491, DOI [10.2307/4440732, DOI 10.2307/4440732]
[5]
CALDWELL LK, 1970, NAT RESOUR J, V10, P203
[6]
Commoner B., 1971, THE CLOSING CIRCLE