I think I've been to every Poser site on the net and I don't recognize those.

You are under no obligation to credit the creator of items, unless you want to.  I usually try to credit freebie providers because they get nothing but a thank you, if that.  Sometimes i'll credit a merchant, but it largely depends on my mood at the time i'm uploading my image.   The new credit system in the gallery is a royal PITA so mostly I don't bother anymore.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi