https://en.wikipedia.org/wiki/Barend_Klaas_Kuiper

https://wellsofgrace.com/books/spiritual/2000years/index.html

https://www.exodusbooks.com/b-k-kuiper/788/

https://www.logos.com.hk/bf/acms/content.asp?site=logosbf&op=show&type=product&code=9575870115