A novel chaotic system in the spherical coordinatesLianyu Chen, Esteban Tlelo-Cuautle, Ibrahim Ismael Hamarash, Viet-Thanh Pham and Hamid Reza AbdolmohammadiEur. Phys. J. Special Topics, 229 6-7 (2020) 1257-1263DOI: https://doi.org/10.1140/epjst/e2020-900246-1