General Study: http://www.coe.int/en/web/freedom-expression/study-filtering-blocking-and-take-down-of-illegal-content-on-the-internet
Country reports and State comments: http://www.coe.int/en/web/freedom-expression/country-reports
Bulgarian Study:
General Study: http://www.coe.int/en/web/freedom-expression/study-filtering-blocking-and-take-down-of-illegal-content-on-the-internet
Country reports and State comments: http://www.coe.int/en/web/freedom-expression/country-reports
Bulgarian Study: