Rinomhota, A. Shupikai, author
Churchill Living Stone, 2000
Buku Teks
[edited by] Katherine M. Fortinash, Patricia A. Holoday Worret
St Louis , 2004
Buku Teks
Cook, J. Sue
Addison Wesley Publishing, 1987
Buku Teks
[edited by] Elizabeth M. Varcarolis
Saunders, 1990
Buku Teks
edited by Barbara Schoen Johnson
J.B. Lippincott , 1986
Buku Teks