Modules
UG-2.2.1
Rulebook Volumes are subdivided into Modules, arranged in groups according to their subject matter, underneath the headings listed in paragraph UG-2.1.3 above.
UG-2.2.2
Each Module in a Volume is referenced using a two-letter code which is usually a contraction or abbreviation of its title. These codes are used for cross-referencing within the text.