  Dispersion, attenuation and wavefronts in a class of linear viscoelastic
media proposed by Strick and Mainardi in 1982 and a related class of models due
to Lomnitz, Jeffreys and Strick are studied by a new method due to the Author.
Unlike the previously studied explicit models of relaxation modulus or creep
compliance, these two classes support propagation of discontinuities. Due to an
extension made by Strick either of these two classes of models comprise both
viscoelastic solids and fluids.
