Pada 1970, Lefebvre membentuk Serikat St.PiusX (SSPX). Pada 1988, bertentangan dengan larangan dari Paus Yohanes PaulusII, ia mengkonsekrasikan empat uskup untuk melanjutkan karyanya dengan SSPX. Tahta Suci kemudian mendeklrasikan bahwa ia dan uskup-uskup lainnya yang berpartisipasi dalam acara tersebut secara otomatis di-ekskomunikasi dibawah hukum kanon Katolik.[Notes 1] Pada 2009, 18 tahun setelah Lefebvre meninggal, Paus Benediktus XVI menarik status ekskomunikasi dari empat uskup yang masih hidup atas permintaan mereka.[3]
Lefebvre, Marcel (1987). Open Letter to Confused Catholics. Kansas City, Mo.: Angelus Press. ISBN978-0-935952-13-1. Translated from the original book: Lefèbvre, Marcel (1985). Lettre Ouverte aux Catholiques Perplexes (dalam bahasa French). Paris: A. Michel. ISBN978-2-226-02325-4. Pemeliharaan CS1: Bahasa yang tidak diketahui (link)
Lefebvre, Marcel (1997). Against the Heresies. Kansas City, Mo.: Angelus Press. ISBN978-0-935952-28-5.
Lefebvre, Marcel (1988). They have Uncrowned Him: from Liberalism to Apostasy, the Conciliar Tragedy. Dickinson, Tex: Angelus Press. ISBN0-935952-05-5.
Lefebvre, Marcel (2001). Religious Liberty Questioned – The Dubia: my Doubts about the Vatican II Declaration of Religious Liberty. Kansas City, Mo.: Angelus Press. ISBN978-1-892331-12-0.
Lefebvre, Marcel (2007). The Mass of all time: the hidden treasure. Kansas City, Mo.: Angelus Press. ISBN978-1-892331-46-5.
Catatan
↑Code of Canon Law 1983, Canon 1382: A bishop who consecrates some one a bishop without a pontifical mandate and the person who receives the consecration from him incur a latae sententiae excommunication reserved to the Apostolic See
↑A convinced monarchist, he devoted himself during the whole of his life to the cause of the French Dynasty, seeing in a royal government the only way of restoring to his country its past grandeur and a Christian revival.A Calvary 1941–1944 René Lefebvre Part 1, June 1984, Volume VII, Number 6, The Angelus
12Monsignor Lefebvre in his own words di www.sspxafrica.com Galat: URL arsip tidak dikenal(diarsipkan tanggal 20061206183348). Serikat St. Pius X – Afrika Selatan. sspxafrica.com. Februari 2002.
Dinges, William D. (2003). "Marcel Lefebvre". Dalam Catholic University of America (ed.). New Catholic Encyclopedia. Vol.8 (Jud–Lyo) (Edisi 2d). Washington, D.C.: Gale. hlm.446–449. ISBN0-7876-4004-2.
Filipazzi, Antonio G. (2006). Rappresentanze e Rappresentanti Pontifici dalla Seconda Metà del XX secolo. Città del Vaticano: Libr. Ed. Vaticana. ISBN88-209-7845-8.
Laudenschlager, Douglas (February 1978). "The Validity of Holy Orders". The Angelus. Arlington: Angelus Press. Diarsipkan dari asli tanggal 2011-09-25. Diakses tanggal 17 August 2011. ;
Lefebvre, Marcel (1987). Open Letter to Confused Catholics. Kansas City, Mo.: Angelus Press. ISBN978-0-935952-13-1.
Tissier de Mallerais, Bernard (2004). Marcel Lefebvre: The Biography. Kansas City, Mo.: Angelus Press. ISBN1-892331-24-1. The official biography of Lefebvre, originally published in French (Clovis, 2002).
Code of canon law (Edisi Latin-English). Washington, D.C.: Canon Law Society of America. 1983. ISBN0-943616-19-0. Diakses tanggal 17 August 2011. First English translation of the 1983 "Codex Iuris Canonici" published by the Libreria Editrice Vaticana.