As this article doesn't contain an abstract, the image below is necessary to enable the article to be indexed by certain search engines. The resolution of the full-text PDF is much higher than that shown here.
c1 Profesor Asociado de Organizatión de Empresas (Universidad de Oviedo), E.U.I.T.I. Avda. de Manuel Llaneza, núm 75, 33210, Gijón (ASTURIAS), ESPAÑA; (e-mail) delbrio@opalo.etsiig.uniovi.es.