infoRouter
AODocs
Docomotion
OpenKM
Zoho Docs
SPDocKit
SmartVault
PaperVision Enterprise
Qiqqa
Mendeley
Zotero
JabRef
Citavi
Docear
Paperpile
BibDesk
infoRouterQiqqa is by far the strongest solution for research and managing pdf's. Zotero, named as a comparison is weak as it does not allow pdf;s to be loaded into its interface - you need to use a pdf reader, which defeats its whole purpose. With Qiqqa documents in a library can be searched together. It has excellent maps of your libraries. It is not prefect, having a few glitches, but still is the only one of its kind.
AODocs - AODocs is the document management solution recommended for G Suite. Secure your documents, structure your content, & automate your processes
Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.
Docomotion - Docomotion offers tools for designing and generating all types of transactional and operational business documents.
Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.
OpenKM - OpenKM is an easy to use powerful version control system that enables businesses efficiently and systematically capture, store, secure, manage, maintain and distribute corporate information assets with the goal of facilitating knowledge creation, op…
JabRef - Graphical Java application for managing bibtex (. bib) databases.JabRef · JabRef Help · JabRef | Blog · OpenOffice/LibreOffice .