Emergence of a square chaotic attractor through the collision of heteroclinic orbitsHéctor E. Gilardi-Velázquez, Rodolfo J. Escalante-González and Eric CamposEur. Phys. J. Special Topics, 229 6-7 (2020) 1351-1360DOI: https://doi.org/10.1140/epjst/e2020-900219-4