Sources:

"British Kings and Queens" Mike Ashley, Carroll & Graf, NY 1998
"The Celts" Gerhard Herm
"The Celts, A History" Peter Berresford Ellis
"The Celtic Realm" Myles Dillon & Nora Chadwick, Phoenix Press 2000
"The Encyclopedia of World History" William L. Langer
"History of Britian" Sir George Clark, Oxford University Press, NY 1972
"A History of England" David Harris Wilson
"The Celts" Gerhard Herm
"The Celts", Juliette Wood, Duncan Baird 1998
World Book Encyclopedias

Early Celts and Druids writers: (information purposes)

Aristotle (c 200AD) - Magicus
Clement of Alexandria (c. 150 - 216) Greek theologian converted to Christianity
Dion Chrysostom (c. 100 AD) - Greek Stoic, traveled among the Celts in Bithynia near Galatia
Herodotus (c. 490 - 425) Greek writer & historian
Hippolytus (c. 170 - 236)
Diogenes Laertius
Pliny the Elder Naturalis Historia - Roman colonist who settled with the Celts of Po Valley
Alexander Cornelius Polyhistor (b. 105 BC)
Pomponius (c. 43 AD)
Poseidonius
Ptolemy - Greek philosopher from Alexandria circa 150 AD
Tacitus - Roman who documented Celtic life era 70's BC
Timaeus (c. 356 - 260)
Soton of Alexandria (c. 200 - 170)

Recommended books:

An Anthology of Irish Liturature, David Greene, N.Y. University 1971
The Book of Ogham, Edred Thorsson,
Celtic Heritage, Rees, Alwyn and Brinley, New York, Grove Press, 1961
The Celts, Gerhard Herm, N.Y. 1976
Celtic Myths and Legends, T.W. Rolleston, Bracken Books, N.Y.1985
A Druids Herbal Year, Ellen Hopman
A Druid Renaissance, Phylip Carr Ghom
Encyclopedia of Celtic Wisdom, John and Caitlin Mathews
Focloir Poca Dictionary, An Roinn, Oideachais, Ireland, 1986
The Four Branches of the Mabonogi, Evangeline Walton
The Golden Bough, James George Frazer, N.Y. 1963
Irish Sagas and Folk Tales, Eilee O'Faolain, Oxford University Press, 1971

Stone Hendge Decoded, Gerald S. Hawkins, N.Y.Frazer, 1965
Story of the Irish, Seumas MacManus, Connecticut, USA 1978
Y Geiriadur Bach; a Welsh to English Dictionary, Davies, Christopher