Fenn, Percy T.
D. Appleton-Century, 1948
Buku Teks
Corwin, Edward S.
Holt, Rinehart and Winston, 1964
Buku Teks
Scaros, Constantinos E.
Jones and Bartlett Publishers, 2011
Buku Teks
Corwin, Edward S.
Princeton University press, 1958
Buku Teks
Antieau, Chester James
Dennis & Co., 1960
Buku Teks