16Sheridan, Alison. "Megaliths and Megalomania: An Account, and Interpretation, of the Development of Passage Tombs in Ireland." The Journal of Irish Archaeology 3 (1985/1986): 17-30.
In 2009 traces of megalithic art were discovered in Carrowkeel Cairn B, with a bit more found the next year. As Robert Hensey describes his discovery: "In the course of carefully examining the orthostats within the chamber using oblique lighting, two circular and concentric carved designs became apparent on the top part of orthostat 5." (Hensey, Robert, and Guillaume Robin. "Once Upon a Time in the West." Archaeology Ireland 26.3 (2012): 26-29.) A composite photograph from this article may be seen here.