Hutauruk, T.S., author
Erlangga, 1991
Buku Teks
by Sanjeeva Gupta ... [et al.]
Khana Publishers, 1977
Buku Teks
Artikel Jurnal
[publisher not identified], [date of publication not identified]
Buku Teks
Ganijanti Aby Sarojo, author
FIPIA UI, 1981
Buku Teks