Browsing the Stacks: The section for commentaries, monographs, and edited volumes focusing on Psalms begins at BS 1419.
Numbering: Different traditions number the Psalms differently! It gets complicated, but in general, the chapter numbers in the Hebrew/Masoretic tradition are one ahead of the numbering in the Greek Septuagint/Latin Vulgate tradition (Ps 119 = Ps 118 LXX). Protestant traditions tend to follow Masoretic numbering, while Catholic and Eastern Orthodox traditions tend to follow the Septuagint numbering. Traditions also vary as to whether a psalm's heading counts as a verse -- so verse numbers in different sources might be off by one, too!