this is a good reference for a PMM book - quite new
https://www.svpg.com/books/loved-how-to-rethink-marketing-for-tech-products/
also read about Product Management - https://www.svpg.com/books/inspired-how-to-create-tech-products-customers-love-2nd-edition/
On positioning:
the classic: Positioning from All Ries, Jack Trout
the newer: Obviously Awesome - April Dunford