Parmley, Robert O., author
McGraw-Hill, 1981
Buku Referensi
edited for the Australian Institute of Agricultural Science by R.L. Reid.
Butterworth, 1990
Buku Referensi
Kaplan, Laura G., author
McGraw-Hill, 1996
Buku Referensi
Fassett, Norman C.
University of Wisconsin Press, 1985
Buku Referensi
Salmon, William A., author
[American Management Association, ], 1999
eBooks