Cameron L. Key, Aaron P. Smull, Donald J. Estep, Troy D. Butler, and Branislav M. Notaroš. “Adjoint Methods for Uncertainty Quantification in Applied Computational Electromagnetics: FEM Scattering Examples”. Applied Computational Electromagnetics Society Journal (ACES), vol. 34, no. 02, Feb. 2019, pp. 213-5, https://journals.riverpublishers.com/index.php/ACES/article/view/8599.