Murray, William G.
The Iowa State University, 1963
Buku Teks
Hamilton, Alexander, author
Columbia University Press , 1934
Buku Teks
Shepherd, Geoffrey S., author
Iowa State University Press, 1968
Buku Teks
edited by E.L. Baum, Howard G. Diesslin and Earl O. Heady
Iowa State University Press, 1961
Buku Teks
Benedict, Murray R.
Univ. of California Vavision of Agricultural Science , 1960
Buku Teks