Davis, Gordon B., author
Pustaka Binaman Pressindo, 1995
Buku Teks
Davis, Gordon B., author
Pustaka Binaman Pressindo, 1993
Buku Teks
Siagian, Sondang P., author
Rineka Cipta, 2001
Buku Teks
Siagian, Sondang P., author
Rineka Cipta , 1992
Buku Teks
Davis, Gordon B., author
Pustaka Binaman Pressindo, 1991
Buku Teks