“This is clearly a book aimed at specialists in control theory. It is more a monograph … .” (Bill Satzer, MAA Reviews, November 28, 2021)“This book offers a useful reading and provides interesting classroom material on the theory of finite-element indirect methods for optimal control problems.” (Fernando Lobo Pereira, Mathematical Reviews, July, 2021)“The book will become a valuable reference for researchers, engineers and students in the field of mathematics, management science, operations research, optimal control science and economics.” (Savin Treanta, zbMATH 1444.93002, 2020)