Vídeo com explicação: https://www.youtube.com/watch?v=xLSfUreEmUY
Link 1: http://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-6874.php
Link 2: http://www.english-grammar-lessons.com/goingtoorwill/exercise5.swf
Link 3: http://sites.uclouvain.be/gramlink/Gramlink-AN/exercices/futur/futur02.htm