I agree that this is a problem that hasn't been solved yet. Two things I do: - Label papers in Google scholar. It's a bit of a pain though. - I put all the PD

I agree that this is a problem that hasn't been solved yet. Two things I do: - Label papers in Google scholar. It's a bit of a pain though. - I put all the PDFs into Dropbox and have a folder hierarchy. I can access Dropbox from all my devices and 3rd party apps.