1. R. Gurtler and D. Hestenes, J. Math. Phys., 16, 573 (1975).
2. D. Hestenes, Am. J. Phys., 47, 399 (1979).
3. Aristotle, Physics [ http://pinkmonkey.com/dl/library1/aris20.pdf ].
4. M. Maimonides, The Guide for the Perplexed, Unabridged Dover Edition (Paperback - 1956).
5. I. Barrow, Geometrical Lectures [ http://ia700300.us.archive.org/load_djvu_pplet.php?file=19/items/geometricallectu00barruoft/geometricallectu00barruoft.djvu ].