Blonskyi, I. V., Kadan, V. M., Dergachev, A. A., Shlenov, S. A., Kandidov, V. P., Puzikov, V. M., & Grin’, L. O. (2018). Filamentation of Femtosecond Vortex Beam in Sapphire. Ukrainian Journal of Physics, 58(4), 341. https://doi.org/10.15407/ujpe58.04.0341