Ulrich Abel. Problem 10827. The American Mathematical Monthly, 107(8):752, 2000. [doi]
@article{Abel00, title = {Problem 10827}, author = {Ulrich Abel}, year = {2000}, url = {http://www.jstor.org/stable/2695480}, researchr = {https://researchr.org/publication/Abel00}, cites = {0}, citedby = {0}, journal = {The American Mathematical Monthly}, volume = {107}, number = {8}, pages = {752}, }