2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/6537Gravitational microlensing provides a unique technique to reveal information about extragalactic planets. A network of at least four 2m-class telescopes distributed around the northern hemisphere could probe 15-35 jupiters and 4-10 saturns around M31 stars per year.2 pages, LaTeX using newpasp.sty (supplied). To appear in the proceedings of the XIXth IAP colloquium "Extrasolar Planets: Today and Tomorrow" held in Paris, France, 2003 June 30 -- July 4, ASP Conf. SerAstrophysicstext