Dell™ Latitude™ E5400 and E5500 Setup and Quick Reference Guide" (Latitude E5400 Owner's Manual)

http://www.monperrus.net/martin/Linux+on+a+DELL+Latitude+E5400(basic and incomplete)

http://www.linlap.com/wiki/dell+latitude+e5400 (very basic and incomplete)

http://www.guido-flohr.net/dell/latitude-d820/ (for the Latitude D820)