Written declaration by your employer in Germany

Hi,
I am planning to move to Germany from India and I have got a job offer. So, if I understood the process correctly, now I am supposed to apply for the EU Blue Card. So, while going through some forums and links I understand that my employer will need to provide a written declaration apart from the job contract but I am not too sure about the contents of this declaration and was wondering if there is any specific format for the same. I went through the below link but unfortunately this does not provide much information.
http://www.eu-bluecard.com/how-to-apply … __employer

So, anyone any idea about this declaration and if could help me with some sample document so that I may ask my employer as they are not too sure about this document?

Regards,
Subhankar