Dłubakowska-Puzio, E. K., M. Karpuk, and K. Puzio. “Analysis of Tourism Service Quality in Kołobrzeg Region by Means of Time Series Models”. Comparative Economic Research. Central and Eastern Europe, vol. 15, no. 4, Mar. 2013, pp. 31-44, doi:10.2478/v10103-012-0024-8.