Some upgrades to the site's backend have been completed today. As part of this, the site now displays more complete and concise Release History for Phantasy Star products on their respective pages. For example, at the bottom of the Phantasy Star II page, you can see all the times that game has been released. This type of detail is also on pages of publications as well.
We may be missing a few releases, particularly ones from regions other than the UK, North America, and Japan. If you know of a missing release, let me know and I'll look into adding that info.