Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

In page Boris III of Bulgaria:

"

Following Boris's death, his six-year-old son, Simeon II, acceded to the throne, with a Regency Council appointed to exercise royal authority, headed by Boris’s brother, Prince Kiril of Bulgaria.[citation needed]