edited by Joseph D. Noshpitz
John Wiley & Sons, 1997
Buku Referensi
edited by Carolyn Uhlinger Shantz and Wiliard W. Hartup
Cambridge , 1995
Buku Teks SO
McDonald, Ralph E.
Mosby , 1987
Buku Teks SO
Pressley, Michael
Guilford Press, 2007
Buku Teks
Semrud-Clikeman, Margaret
Allyn and Bacon, 1995
Buku Teks SO