Wu Wei Chao. Problem 10988. The American Mathematical Monthly, 110(1):59, 2003. [doi]
@article{Chao03-1, title = {Problem 10988}, author = {Wu Wei Chao}, year = {2003}, url = {http://www.jstor.org/stable/3072351}, researchr = {https://researchr.org/publication/Chao03-1}, cites = {0}, citedby = {0}, journal = {The American Mathematical Monthly}, volume = {110}, number = {1}, pages = {59}, }