1. Grigg, D. (1992). Agriculture in the world economy: An historical geography of decline. Geography, 77(3), 210‒222. http://www.jstor.org/stable/40572192
2. Grubbs, T. J. (n.d.). History of agriculture timeline for 1800‒1900. https://www.timetoast.com/timelines/history-of-agriculture-timeline-1800-1900
3. Hansen, S. (1983). Økonomisk vækst i Danmark. Bind II: 1914–1983 (3rd ed.). Københavns Universitets Økonomiske Institut.
4. Henriksen, O. B., & Ølgaard, A. (1969). Danmarks Udenrigshandel 1874–1958. Københavns Universitets Økonomiske Institut.
5. Kim, N.-N. (2018). Korean long-term statistics 1. Seoul National University Press Cultural Center.