[Mark]

There's also these:

http://www.airwar.ru/indexe.html - russian site for aircraft
http://www.fineart.sk/ - For human anatomy references
http://smcars.nd4spdworld.com/forum/index.php - For cars blueprints
http://coldfusion.art.msstate.edu/ca.../thehumanhead/ - Human head modelling resources
http://coldfusion.art.msstate.edu/ca.../thehumanhead/ - Car blueprints