منابع

https://www.usatoday.com/story/news/politics/2019/04/08/white-house-removes-secret-service-director-continuing-homeland-security-upheaval/3402033002

https://www.cnbc.com/2019/04/08/secret-service-chief-is-fired-nbc-news.html

https://www.dhs.gov/person/randolph-d-alles