Joy D. Osofsky and Hiram E. Fitzgerald, editors
John Wiley and Sons, Inc., 2000
Buku Teks
Jay H. Lehr, editor ; Janet K. Lehr, associate editor
McGraw-Hill, 2000
Buku Referensi
McMahon, Linnet
Routledge, 1992
Buku Referensi
Koren, Herman
CRC Press, 2017
Buku Teks
Wolman, Benjamin B., editor
Prentice-Hall, 1982
Buku Teks SO