I have been working with a workplace to change their culture. They are responding well to Nonviolent Communication: A Language of Life by Marshall Rosenberg. I also use his book in three of my classes as one of the textbooks. Here is a site that’s makes it available, free. Start with Disc 1 in Created Playlists: https://www.youtube.com/channel/UChba0vNERFwUtoxlZ6AjrMw