Here is a link that is helpful for all those who want a better grasp on the teachings of Catholicism. Naturally, as missionaries in Italy where the dominant religion is Roman Catholicism, we have no choice but to be well-informed with Roman Catholic Church (RCC) teaching. Thankfully there are brothers like Leonardo De Chirico who can lead evangelicals around the world into a proper understanding of Roman Catholic teaching in order to best evangelize those caught like slaves in the RCC.
That being said, here is a helpful article for your edification. Written by Leonardo and published at Desiring God.