John O'Malley S.J., What Happened at Vatican II (Cambridge: Harvard University Press, 2008), 280-282.
See also Fr. Marie-Dominique, O.P., "INDULGENCES IN THE LIFE OF THE CHURCH PART 3," The Angelus Online(2004)(http://www.angelusonline.org/index.php?section=articles&subsection=show_article&article_id=2354)
Here the reader will find a detailed account of these events as printed in a journal that supports Archbishop Lefebvre. At the end of the article, the author laments how Paul VI was swayed to diminish and falsify the Catholic Doctrine of indulgences in order to attract Protestants back to the true church.