Casado Filho, Petrúcio Lopes. “Copyright Law Vs. Copyleft: Controversies Between Textbook Copyright and Private Photocopying”. The Journal of Intellectual Property – Contemporary Law and Constitution, vol. 2, no. 1, Feb. 2013, pp. 1-97, https://doi.org/10.16928/2316-8080.v2n1p.1-97.