All One Universe (New York, 1996).
Immediately after "Wellsprings of Dream," and the concluding item in the volume, is "The Voortrekkers." See also here. This story incorporates one of the concepts summarized in "Wellspring..."
Immediately before "Wellspring...," is "The Visitor." This was the story that I referred to here.
All One Universe also includes appreciations of:
Johannes V Jensen
There is also a prehistoric story, an alternative history story and an Old Phoenix story. See also here.