I agree that it's to her credit. Maybe when my copy of "Glamoury" arrives, I'll find that she in turn gives credit to her source, as many before her have done in their album sleevenotes.

What struck me about Stick Stock was the rarity of its theme, which, as far as I'm aware, only occurs in one other text, i.e. "Appley and Orangey".

I wouldn't necessarily expect a source for a more common motif to be credited.