Directories in print 1991 : part 2
Gale Research, 1991
Buku Referensi
Directories in print 1991 : part 1
Gale Research, 1991
Buku Referensi
Directory of research in academic year 1996-97
National University of Singapore, [date of publication not identified]
Buku Referensi
Ulrich's international periodicals directory 1991-1992 : volume 1
R.R. Bowker, 1991
Buku Referensi
Ulrich's international periodicals directory 1992-1993 : volume 1
R.R. Bowker, 1992
Buku Referensi