@article {2101.05270, archivePrefix = {arXiv}, eprint = {2101.05270}, primaryClass = {math-ph}, author = {G. Gubbiotti and M. C. Nucci}, title = {Superintegrable systems in non-Euclidean plane: hidden symmetries leading to linearity}, year = {2021}, url = {http://arxiv.org/abs/2101.05270} }