On 13 December, Dr. Weaver posted an article about the EIGHT CHURCH MODES. I thought it might be helpful to create this mode chart (PDF) which gives the various names for each mode of Gregorian Chant. If you notice any errors, please let me know!
Pope Saint Paul VI (3 April 1969): “Although the text of the Roman Gradual—at least that which concerns the singing—has not been changed, the Entrance antiphons and Communions antiphons have been revised for Masses without singing.”