"spitfire pr" is better: http://www.largescal...ype=spitfire pr
That's true, assuming that PR is also listed in the "types" field, but is sometimes not, and then the book won't appear in the listing, even though it's in the database. The AJ Press volume 4 book on the Spitfire is an example. As a general rule, less is more when searching from the home page.
Another example would be Bf 109G-6/R6, vs Bf 109G. The Bf 109G will yield tons of results, the Bf 109G-6/R6 will yield nothing.