XV Meždunarodna naučna konferencija VSU´2015 : dokladi. Tom I, Sofia, Bulgaria, 4. - 5. 6. 2015 = 15th International scientific conference VSU´2015, proceedings. Volume I, Sofia, Bulgaria, 4. - 5. 6. 2015. Sofia : University of Structural Engineering and Architecture "L.Karavelov", 2015. 412 s. ISSN 1314-071X.