2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/87963Seminal result of Delsarte is archived here13 pages, LaTex, forward and translations by H.C. Rosu who is indebted to J. Beckers for kindly sending copy of the work, idioms: original French, English, Romanian, SpanishHistory and Philosophy of Physicstext