 Among his main works are the book "Standardni jezik" ("Standard Language") (1970) and the article "Hrvatski jezik, njegovo mjesto unutar južnoslavenskih i drugih slavenskih jezika, njegove povijesne mijene kao jezika hrvatske književnosti" ("Croatian Language, Its Place among the South Slav and Other Slav Languages, Its Historical Changes as the Language of Croatian Literature") (1978).The former gives a typology of standard languages, which however meets criticism for containing disputable and vague criteria.The latter divides the history of the Croatian language into three pre-standard and three standard periods.