No further written sources exist for the 10th and 11th centuries.

Today, few sources and studies exist about Byzantine music on the whole.

The first is where an independent source of the evidence exists.

Several sources of current news exist about the trade union movement in the world.

Various other sources exist that are not associated with known bodies.

The main difficulty is that no single, complete source of traffic information exists.

Good sources of water, food, and cover exist over its entire length.

Although her source no longer exists, another place to look is hatsbythe100.com.

A second source exists in the form of underground water.

Few sources exist about the early development of the office.