No signature on back ... HOWEVER .. You nailed it potsherd_creek. Following up on your information I did find an etching by Heldner and the signature is an exact match.I looked a bit, Heldner did do dry point etchings in that style so to me that looks right. Of coarse I can not see the etching proof in real life to make a solid assertion. Initialed when sketched, looks like the signature was added at a later time, not that uncommon. Does the picture just happen to have a signature on the back ?