Distance functions were initially defined on the input or output production possibility sets by Shephard (1953, 1970) and extended to a graph representation of the technology by Fare, Grosskopf and ...

VILHELM JØRGENSEN, ON AN INEQUALITY FOR THE HYPERBOLIC MEASURE AND ITS APPLICATIONS IN THE THEORY OF FUNCTIONS, Mathematica Scandinavica, Vol. 4, No. 1 (1956), pp. 113-124 ...