%0 Journal Article %A McLenaghan, R. G. %A Walton, T. F. %T An explicit determination of the non-self-adjoint wave equations on curved space-time that satisfy Huygens' principle. Part I : Petrov type N background space-times %J Annales de l'I.H.P. Physique théorique %D 1988 %P 267-280 %V 48 %N 3 %I Gauthier-Villars %U http://www.numdam.org/item/AIHPA_1988__48_3_267_0/ %G en %F AIHPA_1988__48_3_267_0