Computational Complexity of Approximation Algorithms for Combinatorial Problems. - George Gens; Eugene Levner (MFCS, 1979)

Complexity of approximation algorithms for combinatorial problems: a survey. - George Gens; Eugene Levner (SIGACT News, 1980)

Fast approximation algorithm for job sequencing with deadlines. - George Gens; Eugene Levner (Discret. Appl. Math., 1981)

Optimal strategies for the preventive maintenance of real-time repairable systems. - Eugene Levner; Dror Zuckerman; George Gens; Alexander Ptuskin (System Modelling and Optimization, 1993)

An Approximate Binary Search Algorithm for the Multiple-Choice Knapsack Problem. - George Gens; Eugene Levner (Inf. Process. Lett., 1998)