When citing the Catechism, always include the internal reference (paragraph number). You can access the CCC for free via the Vatican's website (link in the citation).
Footnote:
¹ Catechism of the Catholic Church, accessed January 5, 2017, Vatican.va, para. 1145.
² CCC 1145.
Bibliography:
Catechism of the Catholic Church. Accessed January 5, 2017. Vatican.va.