https://sites.google.com/site/middleschoolandroid/home/app-inventor-tutorials/day-1
http://www.cs.usfca.edu/~wolber/appinventor/locationsensor.html
https://sites.google.com/a/jcu.edu/cs128fall2012/daily-lessons/9-24
http://appinventor.mit.edu/explore/ai2/space-invaders.html
http://www.appinventor.org/book2
http://iot.appinventor.mit.edu
http://puravidaapps.com/snippets.php