Hetherington, Mavis E., author
McGraw-Hill, 1975
Buku Teks
Cobb, Nancy J., author
Mayfield Publishing Company , 2001
Buku Teks
William Damon, editor-in-chief
John Wiley & Sons, 1998
Buku Referensi
Travers, John F.
Scott, Foresman, 1982
Buku Teks
Laybourn, Ann
Edinburgh HMSD , 1994
Buku Teks