In the book "Nagarjuna in Context - Mahayana Buddhism and Early Indian Culture" by Joseph Walser, there's a very interesting chapter which is worth reading (Chapter 5), its called "On the Parasitic Strategies of Mahayana" and discusses the methods used by early Mahayanists to convince people that their texts were the words of the Buddha.

http://www.khamkoo.com/uploads/9/0/0...an_culture.pdf