Zijpp, Nanne van der. "Sonnius, Franciscus (1506-1576)." Global Anabaptist Mennonite Encyclopedia Online. September 2008. Web. 23 Apr 2019. http://gameo.org/index.php?title=Sonnius,_Franciscus_(1506-1576)&oldid=110836.
Zijpp, Nanne van der. (September 2008). Sonnius, Franciscus (1506-1576). Global Anabaptist Mennonite Encyclopedia Online. Retrieved 23 April 2019, from http://gameo.org/index.php?title=Sonnius,_Franciscus_(1506-1576)&oldid=110836.