[1] United Nations. World population day 11 July. https://www.un.org/en/events/populationday/.[2020-06-12].
[2] United Nations. World Population Prospects 2019: Highlights.17 June 2019. https://www.un.org/development/desa/publications/world-population-prospects-2019-highlights.html.[2020-06-12].
[3] National Bureau of Statistics. The total population growth slows down and the level of urbanization continues to rise. http://www.stats.gov.cn/tjsj/sjjd/202001/t20200119_1723861.html.[2020-06-12]. (In Chinese).
[4] National Bureau of Statistics. National data. http://data.stats.gov.cn/easyquery.htm?cn=C01.[2020-06-12]. (In Chinese).
[5] United Nations Population Fund. World population day. https://www.unfpa.org/events/world-population-day.[2020-07-04].