Articles:

• Wikipedia, “Grand Duchy of Moscow”, https://en.wikipedia.org/wiki/Grand_Duchy_of_Moscow

Books:

• Serge A. Zenkovsky, “Medieval Russia's Epics, Chronicles, and Tales”, https://www.bookdepository.com/Medieval-Russias-Epics-Chronicles-Tales-Serge-Zenkovsky/9780452010864 (22,50€)

Videos:

• Smart History of Russia, “Medieval Russia”, https://www.youtube.com/watch?v=woIzqrqNsSs
• Smart History of Russia, “Grand Duchy of Moscow”, https://www.youtube.com/watch?v=YmkUTZcUye4