https://www-adb-org.translate.goog/sites/default/files/publication/747966/global-value-chain-development-report-2021.pdf?_x_tr_sl=en&_x_tr_tl=de&_x_tr_hl=de&_x_tr_pto=nui,sc
https://www.brookings.edu/articles/tripling-zambias-copper-production-a-way-out-of-the-debt-crisis/
https://www.oecd-ilibrary.org/docserver/f97beae7-en.pdf?expires=1646810684&id=id&accname=guest&checksum=AAB69BF9AC6696BD5622F1A55B317C16