https://youtu.be/UQdJs_2lPJM

https://www.nommeraadio.ee/meedia/pdf/RRS/Rockefeller%20Foundation.pdf

https://web.archive.org/web/20120701202148/http://www.rockefellerfoundation.org/uploads/files/bba493f7-cc97-4da3-add6-3deb007cc719.pdf

https://pdf.usaid.gov/pdf_docs/Pcaab500.pdf

https://patents.google.com/patent/US20120251502A1/en

https://patents.google.com/patent/US10130701B2/en