https://github.com/ufpb-computacao/introducao-a-programacao-livro/releases
https://www.ime.usp.br/~elo/IntroducaoComputacao/
https://www.ime.usp.br/~pf/algoritmos/
https://fiorix.files.wordpress.com/2014/04/o-fantc3a1stico-mundo-da-linguagem-c.pdf
http://www.ime.usp.br/~slago/slago-C.pdf