Vasey, Daniel E.
Iowa State University Press, 1992
Buku Teks
Campbell, W. Bruce, editor
[Springer, ], 2012
eBooks
Briggs, David J.
Longman Scientific & Technical, 1994
Buku Teks
Altieri, Miguel A., author
Westview Press, 1987
Buku Teks
editor, Stephen R. Gliessman
Springer-Verlag, 1990
Buku Teks