Vampa, Davide
Palgrave Macmillan, 2016
Buku Teks SO
Lenin, Vladimir I.
Foreign Languages Publishing House , [date of publication not identified]
Buku Teks SO
Havinden, Michael
Routledge, 1993
Buku Teks SO
Conference of Directors of Special Courses, 1987
Buku Teks
Schenk, Gretchen Knief
American Library Association, 1954
Buku Teks SO