Duplicate title to Sanderson, W. & Scherbov, S. ORCID: https://orcid.org/0000-0002-0881-1073 (2017). Introduction. In: Vienna Yearbook of Population Research 2016. Eds. Gietel-Basten, S., Scherbov, S. ORCID: https://orcid.org/0000-0002-0881-1073, & Sanderson, W., pp. 1-3 Vienna, Austria: Austrian Academy of Sciences. ISBN 978-3-7001-8151-4 10.1553 / populationyearbook2016s001.