When writing a paper with lots of citations, there are several tools that can help.
Mendeley is a combination of a desktop application and a website which helps you manage, share and discover both content and contacts in research.
Reference Manager: Generate citations and bibliographies in Microsoft Word, LibreOffice, and LaTeX.
Read and Annotate: Open PDFs and capture your thoughts through sticky notes and highlights.
Add and Organize: Import and organize PDFs from your computer, EndNote™, Papers or Zotero.
Collaborate: Connect with colleagues and securely share your papers, notes and annotations.
Backup, Sync and Mobile: Access your papers on the web, iPhone or iPad.
Network and Discover: Discover papers, people and public groups.