Kelley, Walter G.
Difference equations : an introduction with applications
Academic Press, 1991
 Buku Teks SO
The student and the learning environment
edited by Susan S. Meihofer
National Education Association , 1974
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Wallace, Rebecca M.M.
International law: a student introduction
Sweet & Maxwell, 1986
 Buku Teks SO
Wallace, Rebecca M.M.
International law : a student introduction
Sweet & Maxwell, 1992
 Buku Teks SO
Huddleston, Rodney
A Student's introduction to English grammar
Cambridge University Press, 2006
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