Book one through book three - http://www.baenebooks.com/p-74-the-cobra-trilogy.aspx
Book four http://www.baenebooks.com/p-1081-cob...ar-book-i.aspx
Book Five http://www.baenebooks.com/p-1264-cob...r-book-ii.aspx
Book six http://www.baenebooks.com/p-1514-cob...-book-iii.aspx
Book seven is coming this spring.
The books are organized into two trilogies called the Cobra Trilogy and the Cobra War Trilogy. Read the Cobra Trilogy first. Personally I lump the two trilogies together into one big series that I refer to as the Cobra series. That's why I mention books four, five and six.
There are six books read the cobra trilogy first then the Cobra War trilogy. I explained my jargon above.