Are there any good books out there about the Soviet deportations or any good websites?
Wiki has pretty good article about March 1949 Deportations, very detailed and informative. It’s a good place to start.
I also suggest you read Jaan Kross’s two volumes of “Dear Co-travellers”. He was actually nominated for Nobel prize in Literature for those books.
There are a lot of books in all three languages of the Baltic states, as a lot of deportees have written down their memories.