The official documentation corresponds to the full manual according to the complete description of the model from 2011. The link gives many details both on the background theory for the various components of the model and also references to the all major equation. However, a number of recent development during the latest years are not included.
You may also use the PDF-file that corresponds to the same content but with a format that allow easy printing.
A more recent description of the Current platform gives also links to the latest developlements.