Nichols, Eugene D.
Holt, Rinehart and Winston, 1971
Buku Teks
Horner, Donald H.
Rinehart, 1973
Buku Teks
White, Paul A.
Dickenson, 1970
Buku Teks
Tan, S.T.
PWS Publishing Company, 1994
Buku Teks
Brixey, John C.
Holt, Rinehart and winston, 1954
Buku Teks