id	domain	url
ggj-2473	populationeducation.org	https://populationeducation.org/what-demographictransition-model/)
ggj-2473	www.prb.org	https://www.prb.org/international/indicator/fertility/table
ggj-2473	demoscope.ru	http://demoscope.ru/weekly/ssp/ussr_ed_1935.php
ggj-2473	www.statista.com	https://www.statista.com/statistics/611593/crude-birth-rate-in-europe/
ggj-2473	www.statista.com	https://www.statista.com/statistics/612074/fertility-rates-in-european-countries
ggj-2473	data.un.org	http://data.un.org/glossary.aspx?q=net+reproduction+rate+(surviving+daughters+per+woman