It is possible he received a doctorate back in Russia, but no documents have survived.

Only a few documents in Gothic survive - not enough to completely reconstruct the language.

Its presence was historically confirmed in 1763, but few documents on it survive.

In music, unlike the other arts, few documents survive, and only from the late baroque.

Only a few documents about the history of İbrala survive.

About 20 documents of witch trials during the time from 1574 until 1652 survive.

Certain activities were never shown, for example pyramid building, and written documents concerning such works have not survived.

Few documents written in either the Khitan large or small script survive to this day.

From the first half of the 14th century, a related document has survived.

Where no legal documents survive, he and his family vanish from view.