Matthews, Donald R.
The University of North Carolina Press, 1960
Buku Teks SO
R. Conquest
Macmillan & CO LTD, 1960
Buku Teks
McGraw-Hill, 1955
Buku Referensi
Askeland, Donald R.
Chapman & Hall, 1990
Buku Teks SO
Hall, Donald R.
Arizona The University of Arizona Press, 1970
Buku Teks