Nelson, Gideon E.
John Wiley & Sons, 1984
Buku Teks
Copstead, Lee-Ellen C.
W.B. Saunders , 2000
Buku Teks
Copstead, Lee-Ellen C.
W.B. Saunders, [date of publication not identified]
Buku Teks
edited by Anthony Gale, Michael W. Eysenck
John Wiley & Sons, 1992
Buku Referensi
Winchester, A.M.
D. Van Nostrand , 1965
Buku Teks