Source: https://www.audible.com/pd/Business/How-to-Publish-on-Amazon-Sell-A-Million-Copies-Using-Kindle-Print-Audio-Book-Audiobook/B00WUMEPFW?ref=a_pd_Self-D_c5_lProduct_1_3&pf_rd_p=33155655-0007-48ac-9e07-91de1ab3b1e9&pf_rd_r=8Q25AJX3Q7TPXR0JV8BR&