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Paja M, Estrada J, Ojeda A, Ramón y Cajal S, García-Uría J, Lucas T.Paja M, et al.Postgrad Med J. 1994 Mar;70(821):220-4. doi: 10.1136/pgmj.70.821.220.Postgrad Med J. 1994.PMID: 7910396Free PMC article.