We may perhaps start by throwing all kinds of production into one variable, all consumption into another, and so on, imagining that the notions 'production', 'consumption', and so on, can be measured by some sort of total indices. At present certain examples of micro-dynamic analyses have been worked out, but as far as I know no determinate macro-dynamic analysis is yet to be found in the literature.

p. 173 - Propagation problems and impulse problems in dynamic economics, 1933