1. Sources of included studies.

Trials	MEDLINE	EMBASE	The Cochrane Library	Reference lists	Conference abstracts	Personal contacts	Drugs company
Adcock 1972				+
Bace 2002					+	+
Bass 1969	+		+
Cruickshank 1953			+
Degn 1981	+	+	+
Grob 1981	+	+
Halperin 1997	+	+	+
Halperin 1999	+		+
Henry 1981		+				+
Hoppe 1992	+		+
Langley 2004	+		+
Lebel 2001		+
Strangert 1969	+