Aulas sobre contratos

http://www.youtube.com/watch?v=C1f2RSNiKu4&feature=related Aula 1-parte 1 Contratos

http://www.youtube.com/watch?v=mNkDBJe4VpY&feature=related Aula 1 - parte 2

http://www.youtube.com/watch?v=ir0ogaHRUm4&feature=related Aula 1 - parte 3

http://www.youtube.com/watch?v=-Uq-fMrBI5U&feature=related Aula 1 - parte 4