MEDLINE	EMBASE	PsycInfo	CINAHL
Financial incentives	Monetary incentive	Incentives	Incentives (su)	Physician incentive plans (su)
	Financial incentive	Monetary incentive*	Monetary incentives (su)	Incentive*
	Reimbursement, incentive (su)	Financial incentive*	Financial incentive (kw)	Finance*
	Physician incentive plans (su)	Rewards (su)	Rewards (su)	Monetary*
	Incentive*	Incentive*	Monetary rewards (su)	Lottery
	Reward (su)	Cash	Rewards (kw)	Cash
	Monetary*	Monetary*	Cash (kw)	Reward
	Cash	Lottery	Monetary* (kw)	Reward (su)
	Lottery	Compensation (su)	Lottery (kw)	Compensation
	Compensa*	Compensation	Compensation (kw)	Pay*
	Pay*	Lottery	Pay*	Sell*
	Sell*	Pay*	Sell*	Remunera*
	Financ*	Sell*	Finance*
	Remunera*	Remunera*	Remunera*
Blood	Blood donors (su)	Blood don*	Blood don*	Blood for money
	Blood don*	Morey for blood	Blood trans*	Paid blood donation
	Paid blood*	Paid blood donation	Money for blood	Blood don*
	Money for blood	Blood donation	Paid blood donation	Blood donors (su)
	Blood tansfusion (su)	Blood donor su		Blood transufion (su)
				Exchange transfusion (su)
				Whole blood (su)