See this online ebook:
- The Divine Trinity: A Dogmatic Treatise, by the Rev. Joseph Pohle, Ph.D., D.D., authorized English version with some abridgment and numerous additional references, by Arthur Preuss. With Imprimatur. Volume II of the Dogmatic Theology series of Professor Joseph Pohle and Arthur Preuss.
- The 1st edition (St. Louis, Freiburg, London: B. Herder, 1912) is available at the Hathitrust Digital Library; and in pdf, epub, kindle, and other formats at Internet Archive (linked from this page of Ite Ad Thomam), with a 2nd copy at Internet Archive (linked from “Scholastic’s Bookshelf, Part IV (UPDATED)” at Edward Feser), a 3rd copy at Internet Archive and Open Library (with some pages missing from table of contents), and a 4th copy at Internet Archive and Open Library.
- The 2nd edition (St. Louis, Freiburg, London: B. Herder, 1915) is available at the Hathitrust Digital Library; and in pdf, epub, kindle, and other formats at Internet Archive, with a 2nd copy at Internet Archive.
- “A Meditation on the Feast of the Holy Trinity”, by Msgr. Charles Pope, May 25, 2013, at Community in Mission.
- Conferences on the Blessed Trinity, by the Rev. Dr. J.J. O’Connell, O.S.B. (New York: Catholic Publication Society, 1882). With Imprimatur. May be read online, and available in pdf, epub, kindle/mobi, Daisy, djvu, and txt formats at Open Library and Internet Archive.
- “The Trinity and our spiritual life”, by Father Ryan Erlenbush, 19 June 2011, at The New Theological Movement.
On the Solemnity of Blessed Trinity (Trinity Sunday), 2018.
“And Jesus coming, spoke to them, saying: All power is given to me in heaven and in earth. Going, therefore, teach ye all nations: baptizing them in the name of the Father, and of the Son, and of the Holy Ghost; Teaching them to observe all things whatsoever I have commanded you: and behold I am with you all days, even to the consummation of the world.” (St. Matthew xxviii, 18-20)