“…When defining it, the author did not intend to give a universal model of DUSs, but he believed that its application can contribute to the induction of relevant theoretical assumptions for the delimitation of urban systems in Serbia (Tošić & Nevenić, 2007). Through numerous scientific and professional research, this has been proven and applied in the majority of settlements in Serbia (Drobnjaković et al, 2014;Filipović, 2020;Filipović et al, 2013;Krunić et al, 2009Krunić et al, , 2011; Regionalni prostorni plan opština Južnog Pomoravlja, 83/2010; Regionalni prostorni plan Timočke krajine (Borski i Zaječarski okrug), 51/2011; Regionalni prostorni plan za područje Kolubarskog i Mačvanskog upravnog okruga, 11/2015; Regionalni prostorni plan za područje Zlatiborskog i Moravičkog upravnog okruga, 1/2013; Tošić et al, 2009;Živanović et al, 2021, and other). It is based on research into the spatial manifestation of daily mobility and its impact on the socioeconomic transformation of the city region and its regional system, so that, in addition to the demographic, it also has functional and spatial components, unlike previously used models (Krunić, 2012a).…”