TRANSMISSION OF BALLISTIC LONGITUDINAL AND TRANSVERSAL PHONON PULSES THROUGH A SAPPHIRE-HeII INTERFACE AT T = 0.25 K H.W.M. Salemink, H. van Kempen et P. Wider J. Phys. Colloques, 39 C6 (1978) C6-326-C6-327 DOI: 10.1051/jphyscol:19786144