THE LEVEL AND PRICE VOLATILITY OF BLUEBERRY FRUITS (VACCINIUM CORYMBOSUM L.) OBTAINED BY PRODUCER AND ON THE WHOLESALE MARKET DURING 2007-2016 Journal title: Roczniki Naukowe Stowarzyszenia Ekonomistów Rolnictwa i Agrobiznesu Authors: Wioletta Wróblewska, Eugenia Czernyszewicz Subject(s):