On Johannes Albertus Venter bap 27 May 1747 & Hercules Venter bap 26 Jul 1750,
I've used Delia Robertson's citation to back up the SAG: Prof. Barend J. Venter, "Voorsate staat van Heinricha Venter", 22 September 2008 (e-mail address). This ancestral register was compiled for Delia Robertson on 22 September 2008 from the database "Die Venter familie van Suid-Afrika" compiled by B.J. Venter, J.A. Venter and M.A. Venter. Prof. B.J. Venter, 20 Ray Street, Annlin, 0182. Hereinafter cited as "Voorsate staat van Heinricha Venter."http://www.e-family.co.za/ffy/g6/p6522.htm
It would be good to get his sources though. I'll see if the email address cited on FFYP works.