Fink, Arlene
Thousand Oaks : SAGE PUBLIKATION, 2003,
Buku Referensi
Linda P. Bourque, Eve P. Fielder
Thousand Oaks : SAGE PUBLIKATION, 2003,
Buku Referensi
Sabine Mertens Oishi
Thousand Oaks : SAGE PUBLIKATION, 2003,
Buku Referensi
Linda B. Bourque, Evie P. Filelder
Thousand Oaks : SAGE PUBLIKATION, 2003,
Buku Referensi
Line, Maurice B., editor
Clive Bingley , 1967
Buku Teks