Rolf Färe, Carl Pasurka, Michael Vardanyan. On endogenizing direction vectors in parametric directional distance function-based models.
European Journal of Operational Research, Elsevier, 2017, 262 (1), pp.361 - 369.
〈10.1016/j.ejor.2017.03.040〉.
〈hal-01744614〉 
