2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/13814We discuss the recent developments in the study of alternative detection possibilites offered by the radio technique and air shower arrays.7 pages, Latex (uses sprocl.sty), 3 ps figs., Presented by E. Zas at the Second Meeting on New Worlds in Astrop. Phys., Univ. of Algarve, Faro, Portugal, September 1998. To appear in its proceedingsAstrophysicstext