ISSUEhttps://pubs.nctm.org/view/journals/mt/110/8/mt.110.issue-8.xmlApril 20172019-12-16https://pubs.nctm.org/view/journals/tcm/23/8/tcm.23.issue-8.xmlApril 20172020-01-25https://pubs.nctm.org/view/journals/mtms/22/8/mtms.22.issue-8.xmlApril 20172020-01-25