John, if you are interested in the theoretical work that seems to have
been behind these concepts, you might take a look at:
The Economics of Production
Nicholas Georgescu-Roegen
The American Economic Review, Vol. 60, No. 2, Papers and Proceedings of
the Eighty-second
Annual Meeting of the American Economic Association. (May, 1970), pp. 1-9.
I was fascinated to see G-R's reference to Wicksteed. If G-R is correct
to cite Wicksteed as the source, it would seem that behind the effort to
construct a concept that could be subjected to some sort of measurement
was a general equilibrium theory in which the main driving force was the
demands for particular goods.
Pat Gunning