He studied composition with Kenneth Leighton (his predecessor as Reid Professor of Music at the University of Edinburgh), Egon Wellesz (the first pupil of Arnold Schoenberg), and Witold Rudziński.
Witold Lutosławski | Witold Gombrowicz | Witold Rybczynski | Witold Pyrkosz | Witold Sobociński | Witold Rudzinski | Witold Pilecki | Witold Jakóbczyk | Witold Urbanowicz | Witold Tomczak | Witold Szalonek | Witold Rudziński | Theodore Rudzinski |
Valera was granted a scholarship from the Cuban government in 1965 to study in Poland with renowned composers Witold Rudzinski and Andrzej Dobrowolski.
A large group of his graduates on composition include: Zbigniew Bargielski, Augustyn Bloch, Joanna Bruzdowicz, Wojciech Lukaszewski, Tadeusz Wojciech Maklakiewicz, Boleslaw Ocias, Witold Rudzinski, Marek Sart, Aleksander Szeligowski and Antoni Szuniewicz.