http://gs1.se/en/Standards/Capture/Size-Guide/

http://www.ean-int.org/sites/default/files/docs/barcodes/GS1_General_Specifications.pdf

https://en.wikipedia.org/wiki/International_Article_Number_%28EAN%29

https://en.wikipedia.org/wiki/EAN_5

https://en.wikipedia.org/wiki/EAN_2

https://en.wikipedia.org/wiki/Barcode

http://www.barcodeisland.com

http://www.easesoft.net/Code39-93.html
