1. Arashima, Y., Niwa, Y., Tomikawa, S., Honma, K., Kusakabe, T., & Arai, Y. (2021). Analysis of utility value of barrier-free at railway station facilities and covid-19 countermeasures with contingent valuation method − for the elderly. AIJ Journal of Technology and Design, 27(67), 1464–1469. https://doi.org/10.3130/aijt.27.1464
2. Arrow K., Solow R., Portney P. R., Leamer E. E., Radner R., & Schuman H. (1993). Report of the NOAA panel on contingent valuation.
3. BDL GUS. Accessed December 20, 2021., from https://bdl.stat.gov.pl/BDL/dane/podgrup/tablica.
4. Becla, A., Czaja, S., & Zielińska, A. (2012). Analiza kosztów-korzyści w wycenie środowiska przyrodniczego [Cost-benefit analysis in the valuation of the natural environment]. Difin.
5. Bowker, J. M., Bergstrom, J. C., & Gill, J. (2007). Estimating the economic value and impacts of recreational trails: A case study of the Virginia creeper Rail Trail. Tourism Economics, 13(2), 241–260.