A novel chaotic system in the spherical coordinates Lianyu Chen, Esteban Tlelo-Cuautle, Ibrahim Ismael Hamarash, Viet-Thanh Pham and Hamid Reza Abdolmohammadi Eur. Phys. J. Special Topics, 229 6-7 (2020) 1257-1263 Published online: 26 March 2020 DOI: 10.1140/epjst/e2020-900246-1