Where would someone find the sources used by Catholic believers that led to the catholicism beliefs of Mary?

Where are the facts that possibly show Mary was still a virgin long after she had Jesus, that she didn't die, and that we should use her as a intermediary for our prayers? I'd like to know where in the Bible these statements are founded or just the sources for the theology used. If you decide to comment on this question, may you please use sources so your opinions are backed up. Thank you