Shannon, Ian
F.W. Cheshire, 1955
Buku Teks
Malott, Deane W., author
McGraw-Hill, 1939
Buku Teks
edited by D.B. Williams with contributions by K.O. Campbell ... [and others]
Sidney University Press, 1970
Buku Teks
Metcalf, John E., author
U.S. Department of Agriculture , 1952
Buku Teks
Zagoroff, S.D.
Stanford University Press , 1955
Buku Teks