Smeaton, M. D., R. C. Hughes, J. Vrba, and R. R. Haering. “Nanosecond Acoustic Strain Pulses from CdS Phonon Masers”. Canadian Acoustics, vol. 4, no. 2, Apr. 1976, pp. 30-35, https://jcaa.caa-aca.ca/index.php/jcaa/article/view/390.