"PhilPapers is a comprehensive index and bibliography of philosophy maintained by the community of philosophers. We automatically, continuously index almost all philosophy journals and book publishers. We host the largest open access archive in philosophy. We also index other archives and personal pages for articles by academic philosophers. PhilPapers has over 270,000 registered users."
The Stanford Encyclopedia of Philosophy:
"From its inception, the SEP was designed so that each entry is maintained and kept up-to-date by an expert or group of experts in the field. All entries and substantive updates are refereed by the members of a distinguished Editorial Board before they are made public. Consequently, our dynamic reference work maintains academic standards while evolving and adapting in response to new research. You can cite fixed editions that are created on a quarterly basis and stored in our Archives (every entry contains a link to its complete archival history, identifying the fixed edition the reader should cite). The Table of Contents lists entries that are published or assigned. The Projected Table of Contents also lists entries which are currently unassigned but nevertheless projected."
The Internet Encyclopedia of Philosophy:
The IEP “was founded in 1995 as a non-profit organization to provide open access to detailed, scholarly information on key topics and philosophers in all areas of philosophy. The Encyclopedia receives no funding, and operates through the volunteer work of the editors, authors, volunteers, and technical advisers. At present the IEP is visited by over 500,000 persons per month. The Encyclopedia is free of charge and available to all users of the Internet world-wide. The staff of 30 editors and approximately 300 authors hold doctorate degrees and are professors at colleges and universities around the world, most notably from English-speaking countries.”