Superconducting gap nodes in PrOs_4Sb_12
  We examine the superconducting gap nodes in crystals with tetrahedral (T_h) symmetry. The (0,0,1) phase of the three dimensional order parameter in the triplet channel has nodes in the [001] directions. Following a second order phase transition to the state (0,i|eta_2|,|eta_1|), each node lifts away from the Fermi surface and splits into two deep dips. We discuss this scenario in the context of multiple superconducting phases in PrOs4Sb12. 
S. H. Curnoe, T. R. Abu Alrub, I. A. Sergienko, I. Vekhter