MARQ: an online tool to mine GEO for experiments with similar or opposite gene expression signatures. - Miguel Vázquez; Rubén Nogales-Cadenas; Javier Arroyo; Pedro Botías; Raul García; José María Carazo; Francisco Tirado; Alberto D. Pascual-Montano; Pedro Carmona-Saez (Nucleic Acids Res., 2010)