Getting your 3rd city plans.
Attacking level 1 terrorist camps, will provide the necessary artifacts for your 3rd city. Infantry is the most economical way to do this. Send 100 infantry w/500 supply trucks on attack to the closest level 1 camp. If you repeatedly do this to the same camp, it will not have a chance to regenerate troops,and minimizing your losses . It will also not have a chance to regenerate resources, but will continue to drop artifacts. If your attacking the camp in rapid secession( which is what I just suggested you do)it will not be necessary to send so many supply trucks after the first hit.
3rd city blueprints are set to drop at the rate of 1 in 1000. Dont lose heart, keep at it. It will be very frustrating, but DONT give up.
Deputy Defense Minister