A lot of people value the article known in English as “Of Other spaces” which introduced the term heterotopia and have provided various commentaries on it. Perhaps the most naff was by Edward Soja in books such as Thirdspace.
One of the things we tried to do with “Foucault and Geography”(I prefer the subtitle) was get beyond heterotopia a bit. But there’s no denying that it attracts people, largely, I suspect because they can read whatever they like into its vague phrasing. (And wasn’t the “ship of fools” thing found to just be a literary device, not an actual one?)
More, with link to online text.
Updated: Another heterotopia post. Perhaps I’ll just throw them all in here!