Hi folks, I´m trying to derivate the reflection and transmission factor between solid-solid interface according to prof. Rose´s book "ultrasonic waves in solid media". In this chapter, I´ve found there a few mistakes. however the first two rows in matrix M are correct. Can you please give me advice how to obtain, for example, the third row in matrix M and the third line in vector a respectively? Has anyone made the re derivations? Thank you for help.