OPILSKA, L.; OPILSKI, A.; LATACZ, Z. Relation between the energy. Gap and ultrasonic wave propagation velocities in semiconductors. Archives of Acoustics, [S. l.], v. 5, n. 1, p. 81–90, 1980. Disponível em: http://acoustics.ippt.gov.pl/index.php/aa/article/view/3329. Acesso em: 18 apr. 2026.