The paper presents a description of properties of published spectral data on spectral lines' parameters of sulfur dioxide molecule and its isotopologues. These data were acquired from more than 150 publications for a period of 50 years. Data properties as well as data sources classification according to validity and trust criteria are presented in a form of an ontological knowledge base on information resources. Data source properties values are computed during the checks on validity and publishing criteria [1]. Published ro-vibrational transitions, energy levels, spectral lines' parameters, knowledge base on information resources of sulfur dioxide molecule and its isotopologues are available in the Internet accessible information system W@DIS (http://wadis.saga.iao.ru/).