Hi,
check out this link
http://www5.hrsdc.gc.ca/NOC/English/NOC/2006/Profile.aspx?val=1&val1=1233
As for the reference letter, it should mention most of the duties and responsiblities mentioned by NOC. Some members here advise not to copy paste the exact duties to your reference letter, even though you maybe doing the exact responsibilities. You probably can reword it but still keep the esense of it....But again, I am not an expert...