"For this reason, entrepreneurial activity is just as
necessary a factor in the production of goods as
technical labor services."
> Menger, Carl. (1981) Principles of Economics.
> Translated by James Dingwall and Bert Hoselitz. New
York: New York University Press.
But Menger also wrote:
" Entrepreneurial activity must definitely be counted
as a category of labor services."
(p. 172).
Menger, Carl. 1871 [1976]. Principles of Economics.
Trans. James Dingwall and Bert Hoselitz. New York: New
York University Press
Fred Foldvary