Beta derivative applied to dark and singular optical solitons for the resonance perturbed NLSEAbdullahi Yusuf, Mustafa Inc, Aliyu Isa Aliyu and Dumitru BaleanuEur. Phys. J. Plus, 134 9 (2019) 433DOI: https://doi.org/10.1140/epjp/i2019-12810-0