Ordnance Survey of Ireland, O'Donovan, J., Mawhinney, G., & Ballinascreen Historical Society. (1992). John O'Donovan's letters from County Londonderry (1834): Letters containing information relative to the antiquities of the county of Londonderry collected during the progress of the Ordnance Survey. Ballinascreen Historical Society.

Ordnance Survey of Ireland, et al. John O'Donovan's Letters from County Londonderry (1834): Letters Containing Information Relative to the Antiquities of the County of Londonderry Collected During the Progress of the Ordnance Survey. Ballinascreen Historical Society, 1992.