Eusebius – https://librivox.org/eusebius-history-of-the-christian-church-tr-by-mcgiffert/

Epistle to Diognetus – https://en.wikipedia.org/wiki/Epistle_to_Diognetus

– http://librivox.bookdesign.biz/book/108574

– http://www.earlychristianwritings.com/text/diognetus-roberts.html

Athenagoras – https://en.wikipedia.org/wiki/Athenagoras_of_Athens

– http://www.newadvent.org/fathers/0205.htm

Letter to the Churches in Lyons and Vienne – http://www.earlychristianwritings.com/viennalyons.html

– http://www.earlychristianwritings.com/text/viennalyons.html

Theophilus of Antioch – https://en.wikipedia.org/wiki/Theophilus_of_Antioch

– http://www.newadvent.org/fathers/02041.htm

– http://www.newadvent.org/fathers/02042.htm