https://mathoverflow.net/questions/10860/why-no-abelian-varieties-over-zhttp://www-personal.umich.edu/~asnowden/teaching/2013/679/https://www.math.mcgill.ca/darmon/pub/Articles/Expository/05.DDT/paper.pdfhttps://mathoverflow.net/questions/424694/analogue-of-fermats-little-theorem