The Bulgarian linguist Ivan Duridanov, who improved the most extensive list of toponyms, in his first publication claimed that Thracian is genetically linked to the Baltic languages and in the next one he made the following classification:""The Thracian language formed a close group with the Baltic (resp. Balto-Slavic), the Dacian and the "Pelasgian" languages. More distant were its relations with the other Indo-European languages, and especially with Greek, the Italic and Celtic languages, which exhibit only isolated phonetic similarities with Thracian; the Tokharian and the Hittite were also distant. "" Of about 200 reconstructed Thracian words by Duridanov most cognates (138) appear in the Baltic languages, mostly in Lithuanian, followed by Germanic (61), Indo-Aryan (41), Greek (36), Bulgarian (23), Latin (10) and Albanian (8). The cognates of the reconstructed Dacian words in his publication are found mostly in the Baltic languages, followed by Albanian. Parallels have enabled linguists, using the techniques of comparative linguistics, to decipher the meanings of several Dacian and Thracian placenames with, they claim, a high degree of probability. Of 74 Dacian placenames attested in primary sources and considered by Duridanov, a total of 62 have Baltic cognates, most of which were rated "certain" by Duridanov. For a big number of 300 Thracian geographic names most parallels were found between Thracian and Baltic geographic names in the study of Duridanov. According to him the most important impression make the geographic cognates of Baltic and Thracian ""the similarity of these parallels stretching frequently on the main element and the suffix simultaneously, which makes a strong impression"".