Marine Corps study: <a href="https://web.archive.org/web/20220318001610/https://www.hqmc.marines.mil/Portals/61/Users/019/71/4371/Impacts%20of%20SDA%2020191029.pdf" rel="nofollow">https://web.archive.org/web/20220318001610/https://www.hqmc....</a>