Assertion: glacier | /r/CapableOf | serve as the source of the river
Facets:
Source sentences:
text: But since then both glaciers have been retreating so far that they do not connect anymore (the Upper Aletsch Glacier did retreat about 1.3 km (0.81 mi) from its connecting point with the Aletsch Glacier), but both serve now only as the source of the river Massa.