I've just encountered some recordings by this Netherlands contralto - Oratorio, Bach, Handel, Brahms etc.,
on reissues of her EMI and Philips recordings, late 40's?? through 60's??. Reissued on CD
by EMI France, and Philips/Decca Universal Australia.
She did record on 78, but primarily LP era.
What a lovely voice!!! How is it she is barely known in the USA (based on a very limited survey of friends)???
I see one U.S. release on LP from EPIC.
There is information about her on the Bach Cantatas website: http://www.bach-cantatas.com/Bio/Heynis-Aafje.htm
Those on these lists who are classical vocal enthusiasts - are you aware of her?
Best wishes, Thomas.