"Martin Luther." World History: Ancient and Medieval Eras, ABC-CLIO, 2017, ancienthistory.abc-clio.com/Search/Display/1773486. Accessed 26 Sept. 2017.
"Martin Luther." Britannica School, Encyclopædia Britannica, 13 Aug. 2017. school.ebonline.com/levels/middle/article/Martin-Luther/275557. Accessed 27 Sep. 2017.
