Bibliography
All work stands on the shoulders of giants, and this is the page of all the giants this work stands on.
Apple
Apple II Human Interface Guidelines [Pre-Release Version] (1977-1985)
This is the first Apple HIG, and it's much heavier on the psychology than any other human interface guidelines you can find today. This can help build an understanding of the whys, and not just the whats.
The actual HCI-focused part of the human interface guidelines are as timeless as ever, and you will find much inspiration and knowledge to be gained from here.