¹O'Grady, Standish. The Coming of Cuculain: a Romance of the Heroic Age of Ireland. London: Methuen, 1894. 9.

²Eagleman, David. Sum: Forty Tales from the Afterlives. New York: Vintage, 2010. 23.
Additional information here.

³"Táin Bó Cúailnge." Wikipedia, the Free Encyclopedia. Web. 19 July 2011. <http://en.wikipedia.org/wiki/Táin_Bó_Cúailnge>.
The "Death of Cúchulainn " is a separate story, not included in the Táin Bó Cúailnge. The latter is considered within the Voices from the Dawn project in the entries on Queen Maeve's royal base of Rathcroghan, her tomb of Knocknarea, and the Ulstermen's palace at Emain Macha.

⁴Gregory, Lady Augusta, and W. B. Yeats. Cuchulain of Muirthemne: the Story of the Men of the Red Branch of Ulster. London: J. Murray, 1902. xv.

⁵"Cú Chulainn." Wikipedia, the Free Encyclopedia. Web. 19 July 2011. <http://en.wikipedia.org/wiki/Cú_Chulainn>.
There are a number of variations for the spelling of "Cúchulainn" encountered in the different sources used here. To avoid confusion, we've normalized the spelling of the hero's name. He was born with the name "Sétanta," but it was changed to Cúchulainn, meaning "Culann's Hound," when he was attacked by, and then killed Culann's guard dog. He offered to train a new dog, and in the meantime serve as the guard dog himself. In tradition, Cúchulainn was also known as "The Hound of Ulster."

⁶"Cu Chulainn " The Ulster Cycle. Web. 19 July 2011. <http://ulstercycle.wordpress.com/cu-chulainn/>.
"The Conception of Cú Chulainn Version 1" The Ulster Cycle. Web. 19 July 2011. <http://ulstercycle.wordpress.com/2009/11/07/the-conception-of-cu-chulainn-version-1/>.

⁷Jackson, Kenneth Hurlstone. The Oldest Irish Tradition; a Window on the Iron Age. Cambridge [Eng.: University, 1964. 24.

⁸Gregory 21.
Lady Gregory's translation demonstrates her method of trying to mimic in English the syntax of the Irish language. In 1969, Thomas Kinsella treats a similar passage quite differently:
"And certainly the youth Cúchulainn mac Sualdaim was handsome as he came to show his form to the armies. You would think he had three distinct heads of hair – brown at the base, blood-red in the middle, and a crown of golden yellow. This hair was settled strikingly into three coils on the cleft at the back of his head. Each long loose-flowing strand hung down in shining splendour over his shoulders, deep-gold and beautiful and fine as a thread of gold. A hundred neat red-gold curls shone darkly on his neck, and his head was covered with a hundred crimson threads matted with gems. He had four dimples in each cheek – yellow, green, crimson and blue – and seven bright pupils, eye-jewels, in each kingly eye. Each foot had seven toes and each hand seven fingers, the nails with the grip of a hawk's claw or a gryphon's clench." (Kinsella, Thomas, and le Brocquy, Louis.. The Tain. Oxford [Eng.: University, 1969. 156-58.)

⁹Jackson 15-16.
The Gáe Bulga was thrown with the foot, not the arm. It was given to Cúchulainn by his martial arts teacher, the woman warrior Scáthach. More information here.

¹⁰Cross, Tom Peete, and Clark Harris Slover. Ancient Irish Tales. New York: Barnes & Noble, 1936. 151-52.

¹¹Gregory 237-38.

¹²Kinsella, Thomas, and le Brocquy, Louis. The Tain. Oxford [Eng.: University, 1969. 150-51.
An evocative spoken-work performance of "Cúchulainn's Warp-Spasm" may be heard here.
A musical interpretation may be heard here.

¹³Gregory 336-37.

¹⁴Gregory 339-41.

¹⁵Hull, Eleanor, and Stephen Reid. Cuchulain: the Hound of Ulster. London: Harrap, 1909. 269.

¹⁶O'Grady 152-56.

¹⁷Macalister, Robert Alexander Stewart. Tara, a Pagan Sanctuary of Ancient Ireland. New York: C. Scribner's Sons, 1931. 70.

¹⁸"Cu Chulainn " The Ulster Cycle.
According to W.B. Yeats, "Arguments of a nature purely philological, based upon the language of the texts, or critical, based upon the relations of the various MSS. to each other, not only allow, but compel us to date the redaction of the principal Cuchulain stones, substantially in the form under which they have survived, back to the seventh to ninth centuries." (Gregory, Lady Augusta, and W. B. Yeats. Cuchulain of Muirthemne: the Story of the Men of the Red Branch of Ulster. London: J. Murray, 1902. 355-56.) On p. 23 in their translation, where Cúchulainn explains how he arrived at the scene, is an excellent example of the "puzzle-language" that presents a clue to the antiquity of the sources: "'Which way did you take after that?' "That is not hard to tell,' he said. 'From the Cover of the Sea, over the Great Secret of the Tuatha De Danaan, and the Foam of the horses of Emain, over the Morrigu's Garden, and the Great Sow's back; over the Valley of the Great Dam, between the God and his Druid; over the Marrow of the Woman, between the Boar and his Dam; over the Washing-place of the horses of Dea; between the King of Ana and his servant, to Mandchuile of the Four Corners of the World; over Great Crime and the Remnants of the Great Feast; between the Vat and the Little Vat, to the Gardens of Lugh, to the daughters of Tethra, the nephew of the King of the Fomor.'"

¹⁹"Cu Chulainn " The Ulster Cycle.
Other translations and interpretations included Eleanor Hull's The Boys' Cuchulain (1904), and Yeats' plays, On Baile's Strand (1904), The Green Helmet (1910), At the Hawk's Well (1917), The Only Jealousy of Emer (1919) and The Death of Cuchulain (1939).

²⁰"The Death-place of an Irish Hero." Irish Identity. Web. 19 July 2011. <http://www.irishidentity.com/stories/cuchulainn.htm>.

²¹Kinsella xiii.
Pillar stones are frequently used to identify an action with a specific place. These stones, already ancient at the time of the Tain, often are used as a scene of violence. Kinsella presents, as an example, a scene when a court fool and a girl arrive to deceive Cúchulainn (p. 141): "...Cúchulainn went to meet them and knew by the man's speech that he was the camp fool. He shot a sling-stone from his hand and pierced the fool's head and knocked out his brains. Cúchulainn went up to the girl and cut off her two long tresses and thrust a pillar-stone under her cloak and tunic. He thrust another pillar stone up through the fool's middle. Their two standing-stones are there still, Finnabiar's Pillar-Stone and the Fool's Pillar-Stone. Cúchulainn left them like that."

²²Penn, Elan, Richard Marsh, and Frank McCourt. The Legends & Lands of Ireland. New York: Sterling, 2006. 79.

²³Some examples of the diffusion of the Cúchulainn character into popular culture:
The Irish band "The Pogues" have a track called 'The Sick Bed Of Cuchulainn' on their 1985album Rum, Sodomy And The Lash.
Cúchulainn is the protagonist in the 1984 video game Tir Na Nog and its sequel Dun Darach by Gargoyle Games.
A Cúchulainn collectable action-figure may be purchased here.
Louis le Brocquy's illustrations from The Tain may be viewed here.

²⁴Gregory x-xi.