1. Friedlander, F. G. 1958 Sound Pulses .Cambridge University Press.
2. Wanner, J. C. , Vallee, J. , Vivier, C. & Thery, C. 1972 Theoretical and experimental studies of the focus of sonic booms.J. Acoust. Soc. Am. 52,13–32.
3. Cornet, E. P. 1972 Focusing of an N-wave by a spherical mirror.Appl. Res. Lab., Univ. Texas, Austin, Rep. ARL-TR-72–40.
4. Sturtevant, B. & Kulkarny, V. A. 1974 Dynamics of weak shock waves at a focus. Proc. 2nd Inter-Agency Symp. Univ. Res. Transportation Noise, North Carolina State Univ., Raleigh ,pp.402–415.
5. Hayes, W. D. 1968 Similarity rules for nonlinear acoustic propagation through a caustic. 2nd Conf. Sonic Boom Res. (ed. I. R. Schwartz ). N.A.S.A. Special Publ. no. 180,pp.165–171.