Researchr is a web site for finding, collecting, sharing, and reviewing scientific publications, for researchers by researchers.
Sign up for an account to create a profile with publication list, tag and review your related work, and share bibliographies with your co-authors.
Daniel H. Ullman, Daniel J. Velleman, Douglas B. West. Problems and Solutions. The American Mathematical Monthly, 128(3):276-284, 2021. [doi]