What is the best reference / source gathering and citation tool for Mac?

Mendeley Desktop and Zotero are two apps that fit this criteria, but I'm wondering if there are any others that people use? The key points are a database library (hopefully along with an extension that takes webpage metadata and inserts it with the source info) and a citation tool that can give you the correct cite in multiple formats (e.g., Chicago, MPA, APA, Bluebook).
4 recommended
  1. 1
    Giacomo LawranceAuthor of thenerdystudent.com · Written
    Really great tool - available on iOS too. Also has a MS Word plugin, which is super useful.
  2. 1
    Henrique MacedoHead of Product at TAIKAI x Bepro · Written
    Search across reference metadata, full text journal articles, file attachments, and your personal annotations and notes, to locate the research you need in just seconds and insert citations and references from your EndNote library into your manuscript and automatically build a bibliography in over 6.000 styles right from Word.