I went to the online card catalogue (is it really a card catalogue?) and discovered that the Powell library no longer has any volumes of Billy Whiskers, nor do they have Snip, Snap, and Snur. However, I am pleased to tell you they have one copy of the Norwegian Twins, published in 1930, if you wish to check that one out. I cannot find data on how many books the Powell library has had, historically. They must have had several hundred to keep Liz entertained in the 1940s.