I am a relatively new member. So I do not know if members are allowed to recommend books.
But if I am, I enthusiastically recommend REALISTICALLY SPEAKING by Planaria Price.
It is NOT an accent reduction book per se. It helps ESL students pronounce American English properly.
It has received rave reviews. She actually teaches you where to put your tongue in order to achieve a particular sound.
You can google in order to secure a copy.