Welch’s Improved American arithmetic : adapted to the currency of the United States : to which is added a concise treatise on the mensuration of planes and solids / compiled by Oliver Welch ; improved and illustrated with questions adapted to the rules, for the use of schools and academies by an experienced teacher, 660 - Chandler Collection no. 17, Volume: Archives Chandler Collection no. 17. Clarion University Archives.

Welch’s Improved American arithmetic : adapted to the currency of the United States : to which is added a concise treatise on the mensuration of planes and solids / compiled by Oliver Welch ; improved and illustrated with questions adapted to the rules, for the use of schools and academies by an experienced teacher, 660 - Chandler Collection no. 17, Volume: Archives Chandler Collection no. 17. Clarion University Archives. http://as-clarion.klnpa.org/repositories/2/resources/998 Accessed December 17, 2025.