%isogrk3; — Greek Symbols Character Entities
The %isogrk3; parameter entity includes the ISO character entities with the public identifier:
ISO 8879:1986//ENTITIES Greek Symbols//EN
ISO and the W3C are cooperating to provide an official set of character entity references for XML. A description of this set is available at http://www.w3.org/2003/entities/iso8879doc/isogrk3.html