J. Pohrybieniuk, A. Krotliński, A. Dusińska, J. Sokołowska, and M. Chabowski, “Loneliness among surgical patients - measuring levels of loneliness using De Jong Gierveld Loneliness Scale and Revised UCLA Loneliness Scale”, J Educ Health Sport, vol. 12, no. 12, pp. 303–310, Dec. 2022.