Stupka AA. Frequencies of Long-Wave Phonon-Polaritons and Optical Phonons in Diatomic Ionic Crystals. Ukr. J. Phys. [Internet]. 2018 Oct. 24 [cited 2024 Nov. 22];59(8):793. Available from: https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2018512