Bjorck, J., A. Kabra, K. Q. Weinberger, and C. Gomes. “Characterizing the Loss Landscape in Non-Negative Matrix Factorization”. Proceedings of the AAAI Conference on Artificial Intelligence, vol. 35, no. 8, May 2021, pp. 6768-76, doi:10.1609/aaai.v35i8.16836.