1973 U.S. Professional Indoor
The 1973 U . S . Professional Indoor was a WCT men's tennis tournament played on indoor carpet courts at the Wachovia Spectrum in Philadelphia , Pennsylvania in the United States . 
<triplet> 1973 U.S. Professional Indoor <subj> 1973 <obj> point in time <triplet> carpet court <subj> tennis <obj> sport <triplet> Wachovia Spectrum <subj> Philadelphia <obj> located in the administrative territorial entity