Painlevé analysis, integrability and exact solutions for a (2 + 1)-dimensional generalized Nizhnik-Novikov-Veselov equationGui-Qiong Xu and Shu-Fang DengEur. Phys. J. Plus, 131 11 (2016) 385DOI: https://doi.org/10.1140/epjp/i2016-16385-x