oleh Bernat Jody A. Siregar ... [and others]
Karya Mulya, 2007
Buku Teks
edited by Pieter J.D. Drenth, Joseph A. Sergeant, Roelf J. Takens
John Wiley & Sons, 1990
Buku Teks
Kendall, Philip C., author
John Wiley & Sons, 1982
Buku Teks
Andreas A. Yewangoe, author
BPK Gunung Mulia, 2001
Buku Teks
White, Ellen G., author
Indonesia Publishing House, 2001
Buku Teks