The Church on Worship

The USCCB’s page on the Liturgy
The United States Bishops page on the Liturgy

The 3rd Edition of the Roman Missal
The revised translation of the Roman Missal

The Catechism of the Catholic Church
Section 2 describes worship in the celebration of the Christian liturgy

1963 – Sacrosanctum Concilium – Constitution on the Sacred Liturgy
Document from Vatican II on the sacred liturgy

2003 – JPII Chirgraph on the Centenary of Pius X’s motu proprio “Tra le Sollecitudini” on Sacred Music”
Document by JPII celebrating Pius X’s instruction on Sacred Liturgy in light of 100 years  liturgical experience.

2007 – Sing to the Lord: Divine Worship in Liturgy
Document from the United States Conference of Catholic Bishops (USCCB) regarding music in the liturgy