Raoul, McLaughlin (2016). The Roman Empire and the Silk Routes: the Ancient World Economy and the Empires of Parthia, Central Asia and Han China. Havertown: Pen and Sword. ISBN9781473889828. OCLC961065049.
These markings constitute the most easterly evidence of Roman soldiers' movements. James, Marriott (20. august 2013). The oil road: journeys from the Caspian Sea to the city of London. Minio-Paluello, Mika (Updated paperback utg.). London. ISBN9781781681282. OCLC852808221.