Correction to: Surface elastic-based nonlinear bending analysis of functionally graded nanoplates with variable thicknessSaeid Sahmani, Babak Safaei and Fadi AldakheelEur. Phys. J. Plus, 136 9 (2021) 928DOI: https://doi.org/10.1140/epjp/s13360-021-01895-x