Ploettner, Joan, and Eva Tresserras. “An Interview With Yrjö Engeström and Annalisa Sannino on Activity Theory”. Bellaterra: Journal of Teaching and Learning Language and Literature 9, no. 4 (December 31, 2016): 87–98. Accessed August 18, 2026. https://revistes.uab.cat/jtl3/article/view/v9-n4-ploettner-tresserras.