EngeströmY.MiettinenR. (1999). Introduction. In EngeströmY.MiettinenR.PunamäkiR.-L. (Eds.), Perspectives on activity theory (pp. 1–18). Cambridge, UK: Cambridge University Press.
2.
HegelG. W. F. (2009). Hegel’s logic. Pacifica, CA: Marxists Internet Archive Publications. (Original work published 1830)
3.
VygotskyL. S. (1987). Collected works of L.S. Vygotsky (Vol. 1). New York, NY: Plenum. (Original work published 1934)