Names all external modules specific to the Article Authoring DTD, such as the %articleauthcustom-classes.ent; module
<!ENTITY % articleauthcustom-modules.ent PUBLIC "-//NLM//DTD Article Authoring DTD-Specific Modules v2.3 20070202//EN" "articleauthcustom-modules.ent" >
articleauthoring.dtd