The next company to buy something from Monty better get an iron clad agreement never to fork it.
It's GPL. No such agreement could exist. All of the software up until the point of sale would still be GPL and still be forkable due to the nature of the license. Even given that they retain all copyright, Oracle could change the license upon sale and still not be able to enforce such an agreement because of the terms of previously released code.
The best book on programming for the layman is "Alice in Wonderland"; but that's because it's the best book on anything for the layman.