Imágenes gratuitas https://www.nypl.org/blog/2016/01/05/share-public-domain-collections http://parismuseescollections.paris.fr/en/recherche/image-libre/trueq https://www.flickr.com/photos/biodivlibrary/sets/
El arte del código limpio http://mindbodyncode.com/el-arte-del-codigo-limpio/ http://mindbodyncode.com/el-arte-del-codigo-limpio-ii/
Tutoriales Git Tutorial de Git. Manual básico con ejemplos https://rogerdudler.github.io/git-guide/index.es.html https://git-scm.com/book/es/v2
Sitios con APIs https://deckofcardsapi.com/ https://rickandmortyapi.com/documentation/#rest http://avatars.adorable.io/#demo
REST y API Servicio Web (Wikipedia) Guía breve de servicios Web https://www.getpostman.com/ JSON https://jsonplaceholder.typicode.com/ An Introduction to REST and RESTful APIs