Translations :
Dao De Jing : A Philosophical Translation, by Roger T. Ames and David L. Hall; Ballantine, New York;
2003 (note that this is a translation of the MWD sources)
Lao Zi zhi Dao De Jing : Two Literal English Translations, by Bradford Hatcher;
http://www.hermetica.info/LaoziA.htm; 2005
Lao Tzu, Tao Te Ching, by D.C. Lau; Penguin Books, London; 1963 (this is a reasonably literal
translation, with minimal interpretation; note that his 1994 book is an MWD translation)
The Way and Its Power, by Arthur Waley; Grove Press, New York; 1958
These were mostly used for their own explanations of the more difficult passages and ancient Chinese idioms, but were sometimes used for comparison during the translation process.
Ancient Chinese Sources :