def self.source_info
        {
          base_url: 'http://baderlab.org/Data/RoadsNotTaken',
          citation: 'Too many roads not taken: Aled M. Edwards, Ruth Isserlin, Gary D. Bader, Stephen V. Frye, Timothy M. Willson & Frank H. Yu Nature 470, 163-165 (10 February 2011) doi:10.1038/470163a',
          site_url: 'http://baderlab.org/Data/RoadsNotTaken',