Cook, J. Sue
Addison Wesley Publishing, 1987
Buku Teks SO
Fontaine, Karen Lee
Pearson Education, 2003
Multimedia
Rinomhota, A. Shupikai
Churchill Living Stone, 2000
Buku Teks SO
[edited by] Elizabeth M. Varcarolis
Saunders, 2010
Buku Teks SO
[edited by] Elizabeth M. Varcarolis
Saunders, 1990
Buku Teks SO