Pliska and Veliki Preslav: non-invasive research into the urban planning of two early medieval centers - Milo, Peter; Aladzhov, Andrey; Dimitrov, Petar; Havelka, Jan; Manolova-Voykova, Mariya; Milová, Beáta; Rekemová, Anna Mária; Šálka, Dávi; Tencer, Tomáš; Vágner, Michal (2023)