Spence, R. (1991). Clipper, programming guide (2nd ed.). B.P.B. publications.
शिकागो स्टाइल उद्धरणSpence, Rick. Clipper, Programming Guide. 2nd ed. Delhi: B.P.B. publications, 1991.
एमएलए उद्धरणSpence, Rick. Clipper, Programming Guide. 2nd ed. B.P.B. publications, 1991.
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