Isabel Florence Hapgood was the compiler and translator of the Service Book of the Holy Orthodox-Catholic (Greco-Russian) Church which has been described as "a noble and Christian gift indispensable to the understanding of the teachings of the Orthodox-Catholic Apostolic Church" (History of Russian Church Music, N. P. Brill).
- A Linguistic Bridge to Orthodoxy: In Memoriam Isabel Florence Hapgood - by Marina Ledkovsky. A lecture delivered at the Twelfth Annual Russian Orthodox Musicians Conference, October 7-11 1998, Washington, D.C. (PDF)
- Isabel Hapgood - by Fr. Alexey Young (a brief biography)