Ok, I've modified what Peter and Art have done in the bookmarklet (I
plan to move my changes into the Firefox extension, as well).
I've changed the script to remove periods and commas from the source
titles so SFX can resolve abbreviated titles (J. Exp. Biol. doesn't
resolve, J Exp Biol does).
I've also added SFX buttons to citations and books. I added them to
citations because I've actually had a little bit of luck finding the
content even when it's not in Google Scholar, and I added them to books
because they act the same as citations and I'm a little too lazy to make
You can view the modified bookmarklet at: