Von Uexkuell (1909) is mentioned in Maturana 1980a, p. 51, and 1980b, p. 28
(he clearly used the same fragment twice). The term 'Umwelt' is not
mentioned, but it is evidently meant.
Best wishes,
Arno Goudsmit
references:
Maturana, H.R., "Autopoiesis: reproduction, heredity and evolution", in: M.
Zeleny (ed.), Autopoiesis, dissipative structures and spontaneous
social orders. Boulder, Col.: Westview, 1980(a).
Maturana, H.R., "Man and society", in: F. Benseler, P.M. Hejl, W.K. Ko"ck
(eds.), Autopoiesis, communication, and society. The theory of
autopoietic systems in the social sciences. Frankfurt/New York:
Campus, 1980(b).
Maturana, H.R., "What is it to see?", Arch. Biol. Med. Exp., (1983) 16,
255-269.
Maturana, H.R., "The biological foundations of self-consciousness and the
physical domain of existence", in: E.R. Caianiello (ed.), Physics of
cognitive processes. Proceedings of the International Symposium on
physics of cognitive processes, Amalfi, Italy, 16-20 june 1986. New
Jersey: World Scientific Press, 1987.