1. Schunk D. (2006) The German SAVE Survey: documentation and methodology. MEA Discussion-Paper 109-06. MEA – Mannheim Research Institute for the Economics of Aging, University of Mannheim.
2. German Federal Ministry for Health and Social Security (2005) National strategy report on old-age pension provision. http://www.bmas.band.de/BMAS/Redaktion/Pdf/Publikationen/national-strategy-report-on-old-age-pension-provision.
3. Have Iras Increased U. S. Saving?: Evidence From Consumer Expenditure Surveys
4. Essig L. and Winter J. (2003) Item nonresponse to financial questions in household surveys: An experimental study of interviewer and mode effects. MEA Discussion Paper 39-03. MEA – Mannheim Research Institute for the Economics of Aging, University of Mannheim.
5. IRAs and household saving;Gale;American Economic Review,1994