Clark, W.A.V
Sage Publications, 1986
Buku Teks
Appleyard, Reginald T., author
IOM, 1991
Buku Teks
edited by Brian Opeskin, Richard Perruchoud, Jillyanne Redpath-Cross
Cambridge University Press,, 2012
Buku Teks
Kantha, Lakshmi, author
[, Springer], 2012
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