Photos sources:
- https://pixabay.com/bg/;
- https://unsplash.com/;
- http://prirodabg.org/;
- https://bnr.bg;
- https://patepisanici.com;
- https://bg.wikipedia.org;
- https://tourism.kardzhali.org;
- https://ahrida.org;
- https://opoznai.bg.
Sources of information:
- http://www.turistbg.com/bulgaria/na-planina/planini/124-rodopi;
- https://bg.wikipedia.org/;
- Biodiversity in the Rhodopes; Available at: https://irodopi.bg/;
- Information system for protected areas of the Natura 2000 ecological network; Available at: http://natura2000.moew.government.bg/;
- Ministry of Environment and Water; Available at: https://www.moew.government.bg/bg/;
- Paracaloptenus caloptenoides (Brunner von Wattenwyl, 1861); Available at: http://www.pyrgus.de/Paracaloptenus_caloptenoides_en.html;
- Red Book of the Republic of Bulgaria, Volume II - Animals; Available at: http://e-ecodb.bas.bg/rdb/bg/vol2/texts.html;
- https://bg.culturefishtours.com/157-gorchak-fish;
- Barbus plebejus Bonaparte, 1839; Available at: https://www.fishbase.se/summary/Barbus-plebejus;
- https://bg.hrvwiki.net/wiki/italian_barbel;
- Triturus karelinii; Available at: https://amphibiaweb.org/species/4299;
- GREEN BALKANS - Federation of Nature Conservation Associations; Conservation of bats in Bulgaria; Available at: https://greenbalkans.org/prilepi/index.php;
- Bulgarian Society for the Protection of Birds; Available at: http://bspb.org/;
- The birds in Bulgaria; Available at: https://www.birdsinbulgaria.org/;
- Guide for identifying habitats of European importance in Bulgaria. Second, revised and supplemented edition. Sofia, World Wildlife Fund, Danube-Carpathian Program and GREEN BALKANS Federation; Available at: https://www.moew.government.bg/static/media/ups/tiny/filebase/Nature/Natura%202000/Zakoni_naredbi_guidance/manual_habitats_natura2000_bg2009.pdf;
- https://tourism.kardzhali.org;
- https://ahrida.org.
