Pohl, Margaret L.
WM.C. Brown , 1978
Buku Teks SO
Tornyay, Rheba de
John Wiley & Sons, 1982
Buku Teks SO
Reilly, Dorothy E.
Jones and Bartlett , 1999
Buku Teks SO
edited by Susan M. Hincliff
Churchill livingstone , 1979
Buku Teks SO
Tornyay, Rheba de
John Wiley & Sons, 1987
Buku Teks SO