Columbia subject headings:
Drone aircraft--Purchasing.
Reconnaissance aircraft--Purchasing.
United States. Department of Defense--Procurement--Evaluation.
Harvard subject headings:
Drone aircraft--Purchasing.
Reconnaissance aircraft--Purchasing.
United States. Department of Defense--Procurement--Evaluation.
Princeton subject headings:
Drone aircraft--Purchasing.
Reconnaissance aircraft--Purchasing.
United States. Department of Defense--Procurement--Evaluation.