O'Brien, A. P., Mannix, D., Cotter, W. T., De Barra, É., O’Connor, B., Gaelic League of London, & Irish Self-Determination League of Great Britain. (1925). Letters and documents relating to a demonstration organised by Éamonn de Barra for Archbishop Mannix in London, with newspaper cuttings regarding Mannix’s visits to Ireland and England during 1925, a handwritten note by Ó Briain and a flyer for the Mannix demonstration.

O'Brien, Art Patrick, et al. Letters and Documents Relating to a Demonstration Organised by Éamonn De Barra for Archbishop Mannix in London, with Newspaper Cuttings Regarding Mannix’s Visits to Ireland and England During 1925, a Handwritten Note by Ó Briain and a Flyer for the Mannix Demonstration. 1925.