Useful links:

1. Bulgarian customs
http://www.customs.bg/
 
2. Currency Converter
http://www.xe.com/
 
3. Customs Tariff
http://ec.europa.eu/
 
4. NSBS
http://www.nsbs.bg/
 
5. Dimension of containers
http://www.searates.com/
 
6. Incoterms
http://www.i-b-t.net/
   
7. Sofia Airport
http://www.sofia-airport.bg/
 
8. Tracking for air shipments
http://www.traxon.com/
http://www.compu-clearing.com/
http://www.track-trace.com/
http://www.baworldcargo.com/
http://www.austriancargo.com/