Jaap Ketelaar and Sarah Hay

title	ISBN-13 (ISBN-10)	year of publica- tion	other author(s)
Worth Keeping: Global Perspectives on Best Practice in Missionary Retention	978-O-878O8-515-6 (O-878O8-515-7)	2007	Rob Hay · Valerie Lim · Detlef Blöcher