Study Case of Air-Mass Modification over Poland and Romania Observed by the Means of Multiwavelength Raman Depolarization LidarsMontserrat Costa-Surós, Lucja Janicka, Iwona S. Stachlewska, Anca Nemuc, Camelia Talianu, Birgit Heese and Ronny EngelmannEPJ Web of Conferences, 119 (2016) 08008DOI: https://doi.org/10.1051/epjconf/201611908008