00517naa#a2200169#i#450# EN\\bibl\113086 20260119034102.1 2311-1402 20120325b2012####ek#y0engy0150####ca RUS RU Field tourist camps and hiking tours organization safety requirements Journal article Nizhnevartovsk Nizhnevartovsk State University 2012 6 с. Journal article local Tretyakov Alexander Vasilyevich vestnik.nvsu.ru