"What I'm looking for are books from recognized sources and publishers that would give technical and scientific background on permaculture concepts.." etc.
Enter "amazon permaculture" in your search engine and you'll find every page with both of those words on it.. including every book in print, presumably, with "permaculture" in the title or description.
Here's an example. Permaculture the Earth is an internet bookseller exclusively devoted to permie titles:
http://www.permaearth.org/bookstore.html
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