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The 1971 Philadelphia International Indoor Open Championships also called the Philadelphia International Indoor was a WCT and Virginia Slims Circuittennis tournament played on indoor carpet courts. It was played at the Spectrum in Philadelphia, Pennsylvania in the United States. It was the fourth edition of the tournament and was held from February 9 through February 14, 1971. John Newcombe and Rosie Casals won the singles titles.
Tingay, Lance (1971). "US Tournaments". In Barrett, John (ed.). World Tennis' 71 A BP YEARBOOK. London: The Queen Anne Press Ltd. p. 145. ISBN0362000913.
John Dolan (2011). Women's Tennis 1968–84: the Ultimate Guide. Remous. pp. 81, 85.