Heimler, Charles H.
Charles E Merrill, 1977
Buku Teks
McGraw-HIll., 2003
Buku Teks
Simen Andersen Øyen, editor
[, Wageningen Academic], 2012
eBooks
Moore, D. (David), 1942-, author
Cambridge University Press, 2013
Buku Teks
Pomeroy, John H.
Holt, Rinehart and Winston, 1964
Buku Teks