Lean, G. A. (1985). Counting systems of Papua New Guinea: Research bibliography. Department of Mathematics. Papua New Guinea University of Technology.
Chicago-referens (17:e uppl.)Lean, Glendon A. Counting Systems of Papua New Guinea: Research Bibliography. Lae: Department of Mathematics. Papua New Guinea University of Technology, 1985.
MLA-referens (9:e uppl.)Lean, Glendon A. Counting Systems of Papua New Guinea: Research Bibliography. Department of Mathematics. Papua New Guinea University of Technology, 1985.
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