While I can not speak to all papers, I have never encountered a published criteria by any paper manufacturer that addressed "lines per mm". Most of the technical publications related to a given paper address matters such as spectral sensitivity, paper speed, and characteristic curves. I think that the resolving power of the paper is actually a stronger link then some of the factors contributing to the image such as lenses-both taking and enlarging, film and developer choice, and other factors such as flare. It is the last link in the chain and while an important link, every other factor which could be detrimental to the image prior to the printing is amplified in the printing process.