The group Cross References responsibility is to make sure, that the chapter are related to each other and that the mentioning of source is not redundant. It will also help to connect groups which have similar topics and may work together on certain issues.
The group works together with OverallStructure, to ensure that the book in its final state is consistent, but the CRG will concentrate more on sources and team work.
Our tools will be mostly non visible in the book, as our work will happen on discussion pages, email and other not wiki related methods of communication. However, we see our work as most important, as we have to ensure the scientific mentioning of the sources and have an overview over every page written in this project.