^Stuart Anderson. "R. P. Sprague". squaring.net. مؤرشف من الأصل في 2019-05-10. اطلع عليه بتاريخ 2017-06-30. R.P. Sprague published his solution to the problem of squaring the square. Sprague constructed his solution using several copies of various sizes of Z. Moroń's Rectangle I (33x32), Rectangle II (65x47) and a third 12 order simple perfect rectangle and five other elemental squares to create an order 55, compound perfect squared square (CPSS) with side 4205.
^Sitzungsberichte der Berliner Mathematischen Gesellschaft: 333. 2001. {{استشهاد بدورية محكمة}}: الوسيط |title= غير موجود أو فارغ (مساعدة)
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