Regan, J. X., & Pearse, P. (1921). What made Ireland Sinn Fein: The chief political content of Pearse, the Gael of Gaels; something of MacNeill, Ireland's historian, Griffith, Ireland's statistician, and The O'Rahilly, a leader of the volunteers; the result of a year's (1919) study in Ireland of Sinn Fein. The Author.

Regan, John X., and Padraic Pearse. What Made Ireland Sinn Fein: The Chief Political Content of Pearse, the Gael of Gaels; Something of MacNeill, Ireland's Historian, Griffith, Ireland's Statistician, and The O'Rahilly, a Leader of the Volunteers; the Result of a Year's (1919) Study in Ireland of Sinn Fein. The Author, 1921.