Explicit formula for singular vectors of the Virasoro algebra with   central charge less than 1
  We calculate explicitly the singular vectors of the Virasoro algebra with the central charge $c\leq 1$. As a result, we have an infinite sequence of the singular vectors for each Fock space with given central charge and highest weight, and all its elements can be written in terms of the Jack symmetric functions with rectangular Young diagram. 
Reiho Sakamoto