https://en.wikipedia.org/wiki/Tlaxcala
http://www.houstonculture.org/mexico/tlaxcala.html
http://www.aztec-history.com/aztec-empire.html
http://www.latinamericanstudies.org/aztecs/aztec_human_sacrifice.pdf
http://rubens.anu.edu.au/raid1/student_projects97/aztec/ACosWorldView.html/World1a.html
https://en.wikipedia.org/wiki/Spanish_conquest_of_the_Aztec_Empire
http://aztecsandtenochtitlan.com/aztec-names/aztec-boys-names/
http://mexicounexplained.com/three-martyred-children-tlaxcala/
https://www.thoughtco.com/hernan-cortes-and-his-tlaxcalan-allies-2136523
http://www.cs.cmu.edu/~kvs/heraldry/spanish16/male-given-alpha.html
http://www.cs.cmu.edu/~kvs/heraldry/spanish16/
http://www.bcmj.org/premise/history-bloodletting#4
History of Mercury
http://www.dartmouth.edu/~toxmetal/mercury/history.html
https://www.rt.com/news/252985-mexican-tomb-king-mercury/
https://www.history.com/news/7-unusual-ancient-medical-techniques