"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: