General Information:
EU-Community: https://www.daad.de/de/laenderinformationen/
EURES-Portal: https://eures.ec.europa.eu/index_de
Visa:
Visa types and requirements: https://www.mfa.bg/en/services-travel/consular-services/travel-bulgaria/visa-bulgaria
Entry and residence requirements:
Ministry of Foreign Affairs: https://www.mfa.bg/en/
Working in Bulgaria:
Anglo INFO: https://www.angloinfo.com/bulgaria
Social insurance provisions:
National Social Security Institute: https://www.nssi.bg/en/index.html
Anglo INFO: https://www.angloinfo.com/how-to/bulgaria/money/social-security
Tax regulations:
Ministry of Finance: https://www.minfin.bg/en/6
National Revenue Agency: https://old.nra.bg/en/
Bulgaria Income Taxes and Tax Laws: https://taxsummaries.pwc.com/bulgaria/individual/taxes-on-personal-income
European Commission: https://ec.europa.eu/youreurope/business/index_en.htm
Accommodation:
Sofia Apartments: https://www.sofiaapartments.com/
Bulgaria Rental Housing by Area: https://www.sublet.com/
Country information:
Wikipedia: https://en.wikipedia.org/wiki/Bulgaria
Doing Business in Bulgaria: https://archive.doingbusiness.org/content/dam/doingBusiness/country/b/bulgaria/BGR.pdf
Culture Crossing: https://guide.culturecrossing.net/basics_business_student.php?id=32
Further information:
BBC country briefings: http://news.bbc.co.uk/2/hi/europe/country_profiles/1059735.stm
Bulgaria Travel: https://bulgariatravel.org/de/
Bulgarian tourist office: https://bulgariatravel.org/national-tourist-information-center/
Travel Information: https://europa.eu/youreurope/citizens/travel/travel-and-covid/bulgaria/index_en.htm