…for whatever ground thereabouts was unlevel and unfit for the evolutions of cavalry had long before been levelled by the Persians, and made fit for the easy rolling of chariots and for the galloping of horses – Arrian.

for as soon as they approached, the Agrianians and the javelin-men with Balacrus, who had been posted in front of the Companion cavalry, hurled their javelins at some of the horses; others they seized by the reins and pulled the drivers off, and standing round the horses killed them. Yet some got right through the ranks; for the men stood apart and opened their ranks, as they had been instructed, in the places where the chariots assaulted them. In this way it generally happened that the chariots passed through safely, and the men by whom they were driven were uninjured. But these also were afterwards overpowered by the grooms of Alexander's army and by the royal shield-bearing guards – Arrian.

the Persians on the right wing, who had not yet become aware of the flight of Darius, rode round Alexander's left wing and attacked Parmenio in flank – Arrian(3.11-15).

http://www.iranchamber.com/history/achaemenids/arrian_battle_of_gaugamela.php (This is all based on primary account by Arrian)

http://liberalartistry.blogspot.com/2009/07/great-books-plutarchs-biography-of_12.html (Based on Plutarch's account)

http://www.suite101.com/content/the-battle-of-gaugamela-a233158

http://www.livius.org/aj-al/alexander/alexander_z1b.html (This gives a list of all the 'good' sources)

http://books.google.com/books?id=qi0iL6r7v2IC&printsec=frontcover&dq=j+r+hamilton&hl=en&ei=sWWOTdiWG4z4swPshZyECQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDAQ6AEwAA#v=onepage&q&f=false (This is a VERY good book for any references to Alexander)

Christopher