Walker, Warren F.
Saunders College, 1980
Buku Teks
Walker, Warren F.
W.B. Saunders, 1975
Buku Teks
King, Gillian M.
Blackwell Scientific Pub., 1982
Buku Referensi
Walker, Warren F.
Saunders College Pub., 1986
Buku Referensi
Walker, Warens S.
Shoe String Press, 1984
Buku Referensi