Operationalizing Levels of Academic Mastery Based on Vygotsky's Theory: The Study of Mathematical Knowledge
Educational and Psychological Measurement (2015) - Comment
pubmed: 29795820  doi: 10.1177/0013164414534068  issn: 1552-3888  issn: 0013-1644 

Peter Nezhnov, Elena Kardanova, Marina Vasilyeva, Larry Ludlow