The citation for Kuhn's work is:

Trade and Exchange Among the Mohawk-Iroquois: A Trace Element Analysis of
Ceramic Smoking Pipes
Author: Robert D. Kuhn
North American Archaeologist Volume: 8 Issue: 4

Summary:
This study reports the results of a trace element analysis of
Mohawk-Iroquois ceramics. The objective of the research was an attempt to
identify trade ceramics, specifically ceramic smoking pipes, in Mohawk
assemblages. Over 400 ceramic artifacts were analyzed using an X-ray
fluorescence technique to determine their trace element compositions.
Control samples of pottery were utilized to demonstrate differences in the
elemental composition of regional clay resources, and ceramic pipes of
known provenience were then identified as to their probable region of
origin. The results indicate that ceramic pipes were common trade items
among the Mohawk. The trade and exchange of pipes is interpreted as a
phenomenon of Iroquois gift giving and reciprocity involving a material
class of important symbolic value.

        Dan W.