I am trying to track down a PDF of the St. Gregory Hymnal, Complete Edition, with the 1940 supplement. All I am able to find are melody and 2-part versions. Specifically I am looking for a clean version of the Mauro-Cottone Regina Caeli in 4-part, which is only found in the 1940 supplement. Scanning from these older books is hit-or-miss regarding readability and quality.

Searching for this arrangement on CPDL and IMSLP is yielding no results.