General Information:
EU-Community: http://eu-community.daad.de/index.php?id=67
EURES-Portal: https://ec.europa.eu/eures/main.jsp?acro=lw&lang=de&catId=490&parentId=0

Visa: 
Visa types and requirements: https://visareservation.com/lithuania-visa-requirements/ 

Entry and residence requirements:
Ministry of Foreign Affairs: urm.lt/...

Social insurance provisions:
Ministry od Social Security and Labour: socmin.lt/...

Insurance:
Ministry of Foreign Affairs: urm.lt/...

Tax regulations:
Ministry of Foreign Affairs: businesslithuania.com/...
Legal Requirements: ec.europa.eu/...

Country information:
Wikipedia: wikipedia.org/...
Culture Crossing: culturecrossing.net/...

Further information:
BBC country briefings: news.bbc.co.uk/...