D. G. Gusev, M. G. Martem'yanov, I. V. Soboleva, T. V. Dolgova, A. A. Fedyanin, O. A. Aktsipetrov, “Optical third-harmonic generation in coupled microcavities based on porous silicon”, Pis'ma v Zh. Èksper. Teoret. Fiz., 80:10 (2004), 737–742; JETP Letters, 80:10 (2004), 633–637
