http://benji3up2kxewkqfcq7buxk2xd6zwy3zggnurkrm3l4cvwy2iipvyyad.onion/mirrors/gmpdoc/References.html
Montgomery, “Modular Multiplication Without Trial Division”, in
Mathematics of Computation, volume 44, number 170, April 1985. Arnold Schönhage and Volker Strassen, “Schnelle Multiplikation grosser
Zahlen”, Computing 7, 1971, pp. 281-292.