Sifa, Rafet, et al. “Matrix and Tensor Factorization Based Game Content Recommender Systems: A Bottom-Up Architecture and a Comparative Online Evaluation”. Proceedings of the AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment, vol. 14, no. 1, Sept. 2018, pp. 102-8, doi:10.1609/aiide.v14i1.13028.