Doris, Lillian, author
Prentice-Hall, 1970
Buku Referensi
De Vries, Mary Ann, author
Prentice-Hall, 1991
Buku Referensi
Doris, Lillian
Prentice-Hall, 1960
Buku Teks
Bredow, Miriam, author
Gregg Publishing, 1959
Buku Referensi
Becker, Esther R., author
Harper & Row, 1971
Buku Referensi