This theory has recently come under scrutiny as ethnographic and historical studies show that pure barter ... beads were used to facilitate long-distance trade as well as everyday transactions.

These findings show that the long-distance trade routes of the Puebloan people ... The team is now looking to further map the movement of the blue-green mineral across the southwestern United ...

This dramatically changes our understanding of long-distance trade in Northern Europe during the Viking Age. In Proceedings of the National Academy of Sciences, Star and his team describe how they ...