V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):
XPG X/open Portability Guide (X/Open, X-Windows)The Free On-line Dictionary of Computing (30 December 2018):
X/open Portability Guide XPG (XPG) A document which defines the interfaces of the X/Open Common Applications Environment. Version: XPG3. (1994-12-01)