Generation of Gravitational Waves and Scalar Perturbations in Inflation   with Effective $\Lambda$-term and T/S Story
  We argue that gravitational wave contribution to the cosmic microwave background anisotropy at angular scale $\sim 10^0$ may exceed 50% for some models of hybrid inflation producing standard cosmology with the density perturbation slope $n \simeq 1$. 
V.N.Lukash, E.V.Mikheeva