1Baillie, R. Æ. "Portnoo: A Corner in the Donegal Highlands." The Journal of the Royal Society of Antiquaries of Ireland Fifth 10.2 (1900): 149-50.
The author includes a quotation from 1 Peter 1:24. In the essay, he compares the Kilclooney Dolmen with similar structures in the Middle East.

2McNelis, Tony. "Kilclooney Dolmen." Personal interview. 13 July 1979.
The term "tinker," as used by Mr. McNelis in 1979, is today considered offensive. The preferred term is "traveling people." McNelis died on July 4, 2006, and his sister Nellie now (2006) resides there.

3Borlase, William Copeland. The Dolmens of Ireland, Their Distribution, Structural Characteristics, and Affinities in Other Countries. Vol. 1. London: Chapman & Hall, Ld., 1897. 239-40.
According to Borlase, "Partially covered by a flat stone in the circle of stones which surrounds this monument was a spring of clear water at a distance of a few yards E. of the two pillar-stones." This book may be read in its entirety here.

4Evans, E. Estyn. Prehistoric and Early Christian Ireland; a Guide. New York: Barnes & Noble, 1966. 89.

5Herity, Michael. "The Finds from the Irish Portal Dolmens." The Journal of the Royal Society of Antiquaries of Ireland 94.2 (1964): 138.

6Keeling, David, Karen Molloy, and Richard Bradshaw. "Megalithic Tombs in South-West Donegal." Archaeology Ireland 3.4 (1989): 154.
According to the authors, the Neolithic farmers' woodland clearance may have led to a decline in soil fertility and ultimately the growth of blanket bog in the area.

7Harbison, Peter. Personal interview. June, 1979.

Some of the other suggestions for what the dolmen resembles were found here, and here.

9O'Grady, Standish. Early Bardic Literature. London: Sampson Low, Searle, Marston & Rivington, 1879. 80+.

The folklore regarding visitors tossing stones onto the monument is heard at other dolmens in the country; see Co. Louth's Proleek Dolmen for a good example.

11Mac Neill, Maire, Sean O'hEochaidh, and Seamas O'Cathain. Fairy Legends from Donegal. Dublin: University College Dublin Dept. of Irish Folklore, 1977. 279.
The story cited is from Co. Donegal's Bluestack Mountains.