Pieper, F. C., author
CBD Research Ltd., 1978
Buku Teks
Pieper, F. C., author
CBD Research Ltd., 1978
Buku Teks
Thirlway, Hugh, author
Oxford University Press, 2014
Buku Teks
edited by R.G.D. Allen and J. Edward Ely
John Wiley & Sons, 1953
Buku Teks
Mort, David
Gower Publishing Company, 1990
Buku Referensi