2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/121775Previous work done in collaboration with David Brink is reviewed in the light of the recent observation of new charmonium-like resonances which can be interpreted as tetraquarks. In the framework of a schematic quark model the spectrum of $c \bar c q \bar q $ tetraquarks is presented9 pages, 3 figures, typos correctedHigh Energy Physics - Phenomenologytext