Psalm tones explained by Joseph Robert Carroll (and me)

You can buy the book here:
https://shop.musicasacra.com/product/an-applied-course-in-gregorian-chant-joseph-robert-carroll/
or download the PDF here:
https://media.churchmusicassociation.org/books/applied_course_chant_carroll.pdf
Both part of Music Sacra's Sacred Music Resources here:
https://www.churchmusicassociation.org/resources/
While the Corpus Christi Watershed Gregorian chant course is here:
https://www.ccwatershed.org/gregorian/