Bradley, F.H., author
Clarendon Press, 1959
Buku Teks
edited by Hugh LaFollette and Ingmar Persson
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Buku Teks
selected and edited by Wilfrid Sellars and John Hospers
Appleton-Century-Crofts, 1952
Buku Teks
Ertiniara Novaria Prasanti, author
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2014
UI - Skripsi Membership
Husted, Gladys L., author
Mosby , 1995
Buku Teks