He there earned a Licentiate of Sacred Theology in 1942.

He earned a Licentiate from The Royal Conservatory of Music in 1944 at the age of 16.

He went to England where he earned a Licentiate of the Royal Schools of Music in 1941.

He earned a Licentiate of Sacred Theology from the Catholic University in 1909.

He earned a Licentiate of Canon Law from The Catholic University of America in 1937.

He earned a Licentiate of Canon Law from St. Paul's in 1991.

He earned a Licentiate of Sacred Theology from the Gregorian in 1958.

He earned a Licentiate of Canon Law from the Angelicum University at Rome in 1928.

He later earned a Licentiate of Canon Law from the Pontifical Lateran University in 1949.

Clark returned to the Gregorian in 1964, earning a Licentiate of Canon Law in 1966.