In the structure of the Gospels of Ordinary Time in the Roman Lectionary, initiated by the reform of Vatican II and authorised by Pope Paul VI in 1969, the pattern was to assign a major Gospel to each of the three-year cycles. Thus Matthew is read in A, Mark in Year B and Luke in Year C. People often question what about John's Gospel and the obvious answer is that it is liberally used through the Seasons of Advent and Lent Year A, and particularly the Easter Season. I particular a major use of John occurs in Year B with insertions in Mark's Gospel.
Pastoral Liturgy is published by the the University of Notre Dame Australia, School Philosophy and Theology, Fremantle.
Hardiman, R. (2003). The bread of life discourse (Jn 6): The use of John with Mark's Gospel in Year B. Pastoral Liturgy, 33(4-5), 5-7.