2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/38428Searches for contact interactions, leptoquark bosons and excited fermions carried out at the HERA ep collider are presented here. The searches are based on ~ 40 pb^-1 of e+ p data per experiment collected at a centre of mass energy ~ 300 GeV. First results on e- p data collected in 1998-1999 are also presented.3 pages, Talk given at EPS'99 Conference,Tampere, Finland, 15-21 July 1999High Energy Physics - Experimenttext