Mykola Sysyn, Vitalii Kovalchuk, Ulf Gerber, Olga Nabochenko and Bogdan Parneta 2019. Laboratory Evaluation of Railway Ballast Consolidation by the Non-Destructive Testing. Communications - Scientific letters of the University of Zilina. 21, 2 (May 2019), 81-88. DOI:https://doi.org/10.26552/com.C.2019.2.81-88.