Sorry, Jim,
I know Sekowsky's work so well and, as Tiliban noted, he didn't do that many covers. And his Sterling work is legendary. A quick look at After Dark was all it took.
Mark's last one was a book and an artist I didn't know, hence, he got me. I had no idea where or when to look.
C'est la vie, eh?
ps You ALL should know my latest.
Peace, Jim (|:{>