Greece

General Information:
EU-Community: http://eu-community.daad.de/index.php?id=60

EURES-Portal: https://ec.europa.eu/eures/main.jsp?acro=lw&lang=de&catId=490&parentId=0
World Fact Book:  https://www.cia.gov/library/publications/the-world-factbook/geos/gr.html

Visa: 
Visa types and requirements: https://www.mfa.gr/en/visas/

Entry and residence requirements:
Ministry of Foreign Affairs: http://www.mfa.gr/en/
Visa Information: learn4good.com/...
 
Social insurance:
IKA Social Insurance Institute – Greece: ika.gr/...
 
Tax regulations:

Ministry of Economy and Finance: mnec.gr/...

Accommodation:
Hotels and Hostels: reservations.bookhostels.com/...

Country information:
Wikipedia: wikipedia.org/...
Kwintessential - Doing Business in Greece: kwintessential.co.uk/...
Greece Culture: greeka.com/...
 
Further information:
Tourist information: gnto.gr/...
Visit Greece: http://www.visitgreece.gr/