Assertion: postage stamp | /r/HasProperty | separated by perforation
Facets:
value: generally
type: MANNER
value: more recently
type: TEMPORAL
Source sentences:
text: Stamps that are printed on sheets are generally separated by perforations, though, more recently, with the advent of gummed stamps that do not have to be moistened prior to affixing them, designs can incorporate smooth edges (although a purely decorative perforated edge is often present).