Persell, Caroline Hodges
Harper & Row, 1984
Buku Teks SO
MacQueen, Donald R.
Addison-Wesley, 1973
Buku Teks SO
Ross, H. Laurence (Hugh Laurence)
McGraw-Hill, 1973
Buku Teks SO
Brym, Robert J.
Wadsworth and Cengage Learning, 2013
Buku Teks SO
Bell, Earl H.
Harper & Row, 1965
Buku Teks SO