Preston Tunnell Wilson, Kathi Fisler, Shriram Krishnamurthi. Evaluating the Tracing of Recursion in the Substitution Notional Machine. In Tiffany Barnes, Daniel D. Garcia, Elizabeth K. Hawthorne, Manuel A. Pérez-Quiñones, editors, Proceedings of the 49th ACM Technical Symposium on Computer Science Education, SIGCSE 2018, Baltimore, MD, USA, February 21-24, 2018. pages 1023-1028, ACM, 2018. [doi]