JaBref. I don't know whether it works on iPad, but it does the job for me, has many custom export filters and it's dead easy to write your own export (I do it f

JaBref. I don't know whether it works on iPad, but it does the job for me, has many custom export filters and it's dead easy to write your own export (I do it for yearly reporting in arcane format). Icing on the cake: the storage format is just a *.bib file that can be shared, versioned using git, ...