Zakrzewski, Zbigniew. “Microwave-Photonic Networks Based on Single-Mode Multi-Core Optical Fibers”. Photonics Letters of Poland 5, no. 4 (December 31, 2013): pp. 161–163. Accessed January 14, 2026. https://www.photonics.pl/PLP/index.php/letters/article/view/5-57.