edited by J.M. Anderson and J.S.I. Ingram
CAB International, 1993
Buku Referensi
edited by W.A. Paton
Ronald Press, 1955
Buku Teks
Prentice-Hall, 1991
Buku Referensi
editor, Harry Helms [and others]
McGraw-Hill, 1983
Buku Referensi
edited by William J. Hardcastle, John Laver and Fiona E. Gibbon
Wiley-Blackweell, 2013
Buku Teks SO