Preface: A tribute to Professor Enrique Zuazua on his 60th birthdayGiuseppe Buttazzo, Eduardo Casas, Luz de Teresa, Roland Glowinski, Günter Leugering, Emmanuel Trélat and Xu ZhangESAIM: COCV, 27 (2021) E2DOI: https://doi.org/10.1051/cocv/2021089
