According to their 'About' page, The United States Conference of Catholic Bishops (USCCB) is "an assembly of the hierarchy of the United States and the U.S. Virgin Islands who jointly exercise certain pastoral functions on behalf of the Christian faithful of the United States" whose purpose is to "promote the greater good which the Church offers humankind."
This site is "dedicated to providing accurate historical and current information about the liturgies of the Latin (Roman) rite of the Catholic Church." (from their 'About Us' page)
The Official Catalog for the Vatican; it is here that you will find the most up-to-date resources straight from Vatican City.
Beginning in 1926, Liturgical Press is "truly committed to providing religious and spiritual resources of the highest relevance and quality to the Christian community." (from their 'About Us' page)