"Qobustan". unesco.mfa.gov.az. Archived from the original on 2017-12-28. Retrieved 2018-09-26.
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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. Marriott, James; Minio-Paluello, Mika (20 August 2013). The oil road: journeys from the Caspian Sea to the city of London (Updated paperback ed.). London: Verso Books. ISBN9781781681282. OCLC852808221.