Grosjean, Carl. 1. «On the Frequency Shift Resulting from the Perturbation of an Electromagnetic TM Wave-Mode by a Small Metallic Cylinder in a Resonant Cavity. Part 1: Detailed Theoretical Treatment». Rev. Téc. Fac. Ing. Univ. Zulia 18 (1). https://mail.produccioncientificaluz.org/index.php/tecnica/article/view/5466.