This is from one of the people who helped write the toolbox in Matlab. There is a page limit on the Amazon publishing service, so that is why it's posted here[1]. Chapter 14 describes notation for the recurrent networks and explains their training.

[1]:http://hagan.okstate.edu/NNDesign.pdf

If you are comfortable in MATLAB this tutorial is great: https://theclevermachine.wordpress.com/2014/09/11/a-gentle-i...