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 Alexios I Komnenos:

"

It was introduced along with the electrum aspron trachy worth a third of a hyperpyron and about 25% gold and 75% silver, the billon aspron trachy or stamenon,[citation needed] valued at 48 to the hyperpyron and with 7% silver wash and the copper tetarteron and noummion worth 18 and 36 to the billon aspron trachy.[1]