Zimin, I. <https://pure.iiasa.ac.at/view/iiasa/2550.html>  (1976).  Mathematical Modelling in Normative Development Planning.    In:  Overlapping Tendencies in Operations Research Systems Theory and Cybernetics.  pp. 104-106 Switzerland: Birkhäuser Basel.  ISBN 978-3-0348-5793-2 10.1007/978-3-0348-5793-2_8 <https://doi.org/10.1007/978-3-0348-5793-2_8>.