Collection of conferences. - Simovic, Vojislav; Ratkovic, Radoslav; Rakovic, Prvoslav; Dordevic, Jovan; Horvat, Branko; Cobeljic, Dusan; Kukoleca, Stevan; Pasic, Najdan; Jovanovic, Vladimir; Vacic, Aleksandar; Fira, Aleksandar; Soskic , Branislav; et al. (University of Beograd, 1972)