Those are the books that need to be returned to the library. what is the antecedent of the pronoun those?

Some cultural backgrounds have different superstitions or customs, this can play a part in how they decide things. superstitions are important to a culture for example, an asian culture has a superstition about women putting their purses on the ground their money will be gone, therefore people in that culture try everything they can to not let their purse touch the ground in fear of it being true. also like how we avoid walking under ladders in fear of bad luck. customs may also play a key role a custom also know as a tradition, is something people in the culture have been doing for generations as a quick example, if a family has a necklace that the family's mother passes it on to her daughter in so on it's a custom in that family.