Zotero helps me to tame and keep track of a continuous flow of research papers, at least their electronic pdf-incarnation. However, in order to actually read the papers, I still print off quite a few of them. Two years from now I might want to look at the paper copy again - it's easy to find the electronic copy in Zotero - but then I cannot find the paper copy.

Here's my question: how do you link up - if you do - your offline paper copies with the electronic record? I pondered a number of implementation ideas involving a label such as off line "offline copy" and/or to populate the "extra" field with a "shelf mark" for the printed copy (author or day printed) ... and then filing the papers accordingly. But...

...as I won't be the first and only person having this problem I thought I just ask before reinventing the wheel!

Thanks, Stefan