VON DER LIPPE, Elena; SCHMICH, Patrick; LANGE, Cornelia. Advance letters as a way of reducing non-response in a National Health Telephone Survey: Differences between listed and unlisted numbers. Survey Research Methods, [S. l.], v. 5, n. 3, p. 103–116, 2011. DOI: 10.18148/srm/2011.v5i3.4657. Disponível em: https://ojs.ub.uni-konstanz.de/srm/article/view/4657. Acesso em: 25 apr. 2024.