1. H.M. Gibbs, S.L. McCall, T.N.C. Venkatesan: Phys. Rev. Lett.36, 1135 (1976)
2. As customary we refer to absorptive and dispersive OB according to its origin in the absorptive or dispersive part of the atomic polarizability
3. For the sake of clarity, we consistently call throughout this paper detuning the frequency offset between the field and the atomic resonance and mistuning the offset between the field and activity frequencies
4. R. Bonifacio, L.A. Lugiato: Opt. Commun.19, 172 (1976)
5. R. Bonifacio, L.A. Lugiato: Phys. Rev. A18, 1129 (1978)