Day, A. Grove (Arthur Grove), 1904-1994
Robert D. FitzGerald
Twayne, 1974
 Buku Teks SO
The state and economic development : lessons from the Far East / edited by Robert Fitzgerald
Portland, Or. : F. Cass, 1995
 Buku Teks
Robert, D.S.
Islam concise introduction / D. S . Robert
Harper & Row, 1981
 Buku Teks SO
Intonational phonology / D. Robert Ladd
Cambridge University Press, 2008
 eBooks
Ekelund, Robert B. Jr
Economics/ Robert B. Ekelund, Jr. , Robert D. Tollison
Little, Brown & Co., 1986
 Buku Teks SO