APA (7e ed.) Bronvermelding
ebrary, Inc. (2005). Comfort zones: Planning for a fulfilling retirement, fifth edition (5th ed.). Thomson Course Technology PTR.
Chicago (17e ed.) Bronvermelding
ebrary, Inc. Comfort Zones: Planning for a Fulfilling Retirement, Fifth Edition. 5th ed. Boston, MA: Thomson Course Technology PTR, 2005.
MLA (9e ed.) Bronvermelding
ebrary, Inc. Comfort Zones: Planning for a Fulfilling Retirement, Fifth Edition. 5th ed. Thomson Course Technology PTR, 2005.
Let op: Deze citaties zijn niet altijd 100% accuraat.