On the unramified principal series of GL(3) over non-archimedean local   fields
  Let F be a non-archimedean local field and let O be its ring of integers. We give a complete description of the irreducible constituents of the restriction of the unramified principal series representations of GL(3,F) to GL(3,O). 
Uri Onn, Pooja Singla
math.RT