Helfert, Erich A., author
Erlangga, 1997
Buku Referensi
Helfert, Erich A., author
Erlangga, 1991
Buku Teks
Ahmad Jamli
BPFE-Yogyakarta, 1996
Buku Teks
Saragih, Ferdinand Dehoutman, author
Rajawali, 2014
Buku Teks
Saragih, Ferdinand Dehoutman, author
RajaGrafindo Persada, 2014
Buku Teks