Rikardo de Wallingford: Malsamoj inter versioj

*http://pcdsh01.on.br/histrelog1.htm

*http://www.alphatime.com.br/npage1.1.1.a.html

* http://surfin_dude.tripod.com/creative/clocks/wallingford/stalban.html

* http://www.berkshirehistory.com/bios/rwallingford.html