I was innocently looking for something else when I encountered:
In HyTime ISO/IEC 10744:1997 “3. Definitions (3.35)”: graph representation of property values is ‘An abstract data structure consisting of a directed graph of nodes in which each node may be connected to other nodes by labeled arcs.’ (http://xml.coverpages.org/groves.html)
That sounds like a data structure that a property graph can represent quite easily.
Does it sound that way to you?