When I am reading through journal articles I often come across other articles and references that look like they would be good to read as well. Invariably this leads down a bit of a rabbit warren of searching for papers and inevitably losing the initial thread of my thoughts with the original article. In these cases having a scratch pad handy in which I can jot down the references to look up at a later date is useful.

Instead of copying and pasting references into a word processing document or text file I have automated the process with a PopClip extension. I highlight the reference in the PDF that I am reading, click the Scratchpad extension in PopClip and a short shell script appends the selected text to a markdown formatted file (that I keep in DevonThink). I can then go back at a later date and look at the references that I thought might require following up.

The ScratchPad PopClip extension is available for download on my GitHub page.