Greeks Living in the Persian Empire

Jan 2016
United States of America
I was working on some research and I need some help finding sources about this topic. I was going to look at Herodotus, but I feel like I need more sources about Greeks living in the Persian Empire.
May 2013
The abode of the lord of the north
There were Greeks in north western India, the Gandharan provinces as early as 500 BC. Being the erstwhile satrapy of Achaemenid Persia, Gandhara would have been home to several exiled greek communities and artists who served Achaemenids.