  Tournaments are graphs obtained by assigning a direction for every edge in an
undirected complete graph. We give a formula for the number of isomorphism
classes of vertex-transitive tournaments with prime order. For that, we
introduce Cayley tournaments, which are special Cayley digraphs, and show that
there is a one to one identification between the isomorphism classes of
vertex-transitive tournaments with prime order and the isomorphism classes of
Cayley tournaments with prime order.
