Blockchain-based recommender systems: Applications, challenges and future opportunities[J] COMPUTER SCIENCE REVIEW 2022(43) Himeur, Yassine Sayed, Aya Alsalemi, Abdullah Bensaali, Faycal Amira, Abbes Varlamis, Iraklis Eirinaki, Magdalini Sardianos, Christos Dimitrakopoulos, George
