The answer is that the aerospace industry does not fit the textbook model of perfect competition.

ECONOMIST: Peace in our time

We were looking for a new model to be able to reduce the cost of acquiring textbooks and, ultimately, it became a textbook rental model.

FORBES: An Interview with Dan Rosensweig of Chegg

Especially if McGraw Hill were to change the textbook publishing model at the same time.

FORBES: Should Barnes and Noble Break Up? Float Off the Nook To Compete With Amazon and Apple?

Nationwide training courses and presentations were conducted and a textbook based on the Model Curricula was developed.

UNESCO: Communication and Information