Positron annihilation in metal films Valiev, K. A. ; Gol'Danskiǐ, V. I. ; Novikov, Yu. A. ; Rakov, A. V. ; Filimonov, M. K. ; Shantarovich, V. P. Abstract Publication: Soviet Journal of Experimental and Theoretical Physics Letters Pub Date: March 1987 Bibcode: 1987JETPL..45..373V