Jan E. Holly, David Krumm. Morikawa's Unsolved Problem. The American Mathematical Monthly, 128(3):214-237, 2021. [doi]
@article{HollyK21,
title = {Morikawa's Unsolved Problem},
author = {Jan E. Holly and David Krumm},
year = {2021},
doi = {10.1080/00029890.2021.1859919},
url = {https://doi.org/10.1080/00029890.2021.1859919},
researchr = {https://researchr.org/publication/HollyK21},
cites = {0},
citedby = {0},
journal = {The American Mathematical Monthly},
volume = {128},
number = {3},
pages = {214-237},
}