External module in the base DTD Suite that declares the standard MathML XML special character entities sets used in the NCBI Book DTD (or the NCBI Collection DTD)
<!ENTITY % xmlspecchars.ent
PUBLIC
"-//NLM//DTD Archiving and Interchange DTD Suite XML Special Characters Module v2.0 20040830//EN"
"xmlspecchars.ent" >modules.ent