Natural frequency calculation of open laminated conical and cylindrical shells by a meshless methodSonghun Kwak, Kwanghun Kim, Yonguk Ri, Gwangil Jong and Hyonil RiEur. Phys. J. Plus, 135 5 (2020) 434DOI: https://doi.org/10.1140/epjp/s13360-020-00438-0