Randall R. Dipert (Jun 1982), "Set-Theoretical Representations of Ordered Pairs and Their Adequacy for the Logic of Relations", Canadian Journal of Philosophy, 12 (2): 353–374, doi:10.1080/00455091.1982.10715803, JSTOR40231262
Randall R. Dipert (Jun 1982), "Set-Theoretical Representations of Ordered Pairs and Their Adequacy for the Logic of Relations", Canadian Journal of Philosophy, 12 (2): 353–374, doi:10.1080/00455091.1982.10715803, JSTOR40231262
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For a formal Metamath proof of the adequacy of short, see here (opthreg). Also see Tourlakis (2003), Proposition III.10.1.