Fioralba Cakoni is a professor in the Department of Mathematics at Rutgers University, New Jersey. She is coauthor of A Qualitative Approach to Inverse Scattering Theory (with David Colton, 2014). David Colton is a professor in the Department of Mathematical Sciences at the University of Delaware, where he was appointed Unidel Professor in 1996. He is coauthor of A Qualitative Approach to Inverse Scattering Theory (with Fioralba Cakoni, 2014) and Inverse Acoustic and Electromagnetic Scattering Theory, 3rd edition (with Rainer Kress, 2013). Houssem Haddar is Director of Research at the Institut National de Recherche en Informatique et en Automatique (INRIA), Rocquencourt and a part-time Professor at École Polytechnique, Paris. He is a coauthor of Computational Electromagnetism (with with Ralf Hiptmair, Peter Monk and Rodolfo Rodriguez, 2015).