Lockwood, Elise. <br/><br/>
Two undergraduate students' reinvention of the multiplication principle / 
Elise Lockwood and Branwen Purdy. 
 - Reston, Virginia ;   National Council of Teachers of Mathematics ,   May 2019. 
 - Volume 50, pages 225-267 :  illustration ;  24 cm. 
<br/><br/> Journal for Research in Mathematics Education, vol. 50, no. 3, pages 225-267, May 2019. 
<br/><br/><label>Subjects--Topical Terms: </label><br/> Computation<br/>Concept formation.<br/>Mathematical Concepts
<br/><br/><label>Dewey Class. No.: </label>DPer 510.071 J826 November 2017 v. 48 n. 5, Jan-May 2019 v. 50 n. 1-3.