I've became friends with a Seventh Day Adventist who really takes his denomination's theology seriously. He tried to convince me that the Constantine changed the worship day to Sunday. I would like for anyone to recommend books on the following two topics, so I may choose one and give as a gift: (A) The best Reformed book(s), in order of preference, that exegetically proves that the Sabbath was changed to Sunday. It is important that it also mentions the historical aspect of this debate. (B) The best Reformed book(s) that refutes Seventh Day Adventism in general (refutes their various doctrines which contradicts Scriptures).