Zegadlo, Krzysztof, and Miroslaw Karpierz. “Analysis of a Beam Propagation in Optical Fiber Structures With High Step Index”. Photonics Letters of Poland 1, no. 4 (December 31, 2009): pp. 175–177. Accessed April 25, 2024. https://www.photonics.pl/PLP/index.php/letters/article/view/1-59.