As title, but with a focus on the negotiations and the Sino-British Joint Declaration in 1984.
Also welcome: What's the general Historiographical thought around this event?
Not a historian, but I did some historical economic analysis of Hong Kong under the British. I found these to be some useful sources. Not all of them cover modern history, but they're all comprehensive.
A DOCUMENTARY HISTORY OF HONG KONG, GOVERNMENT AND POLITICS STEVE TSANG (HONG KONG UNIVERSITY PRESS) ISBN 9622093922
((This is probably your best bet))
Edge of Empires: Chinese Elites and British Colonials in Hong Kong:John Carroll
Hong Kong's History: State and Society Under Colonial Rule: Tak-Wing Ngo
Good luck