1. Bhattacherjee, A. (2012). Social science research: Principals, methods, and practices. Textbooks Collection, 3. https://digitalcommons.usf.edu/oa_textbooks/3
2. Bishop, J. P., Lamb, L. L., Philipp, R. A., Whitacre, I., Schappelle, B. P., & Lewis, M. L. (2014). Obstacles and affordances for integer reasoning: An analysis of children’s thinking and the history of mathematics. Journal for Research in Mathematics Education, 45, 19-61. https://doi.org/10.5951/jresematheduc.45.1.0019
3. Black, P., & Wiliam, D. (2010). Inside the black box: Raising standards through classroom assessment. Phi Delta Kappan, 92(1), 81-90. https://doi.org/10.1177/003172171009200119
4. Bofferding, L., & Wessman-Enzinger, N. (2018). Exploring the integer addition and subtraction landscape: Perspectives on integer thinking. Springer. https://doi.org/10.1007/978-3-319-90692-8
5. Bofferding, L., Wessman-Enzinger, N., Gallardo, A., Peled, I., & Salinas, G. (July, 2014). Discussion group: Negative numbers: Bridging contexts and symbols. In C. Nicol, P. Liljedahl, S. Oesterle, & D. Allan (Eds.), Proceedings of the Joint Meeting of PME 38 and PME-NA 36 (Vol. 1, pp. 240). Vancouver, Canada.