Map of Sites in Istanbul
A map showing various religious sites in Istanbul.
DK Publishing
https://books.google.com/books?id=WZFfMmjE4uIC&pg=PA110&dq=st+stephen+of+the+bulgars&hl=en&sa=X&ved=0ahUKEwjBy-vW_4zQAhXniFQKHW9uCekQ6AEIKDAC#v=onepage&q&f=false
Penguin
2007
Danu Mudannayake