Buku Referensi
editor, Alvina Treut Burrows
Holt, Rinehart and Winston, 1966
Buku Referensi
Holt, Rinehard and Winston, Inc.
Holt, Rinehart and Winston,Inc, 1966
Buku Teks
Holt, Rinehart and Winston, 1966
Buku Referensi
Freund, John E., author
McGraw-Hill, c1966
Buku Teks