Sobczak, Wioleta, Lilianna Jabłońska, and Grzegorz Klimek. 2014. “VARIABILITY AND CORRELATION OF THE WHOLESALE AND RETAIL PRICES OF APPLES ON THE WARSAW MARKET IN THE YEARS 2003-2013”. Acta Scientiarum Polonorum. Oeconomia 13 (3), 117-26. https://js.wne.sggw.pl/index.php/aspe/article/view/4135.