@article{SM_2006_197_1_a6,
     author = {K. A. Shramov},
     title = {On the rationality of non-singular threefolds with a pencil of {Del~Pezzo} surfaces of degree~4},
     journal = {Sbornik. Mathematics},
     pages = {127--137},
     publisher = {mathdoc},
     volume = {197},
     number = {1},
     year = {2006},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_2006_197_1_a6/}
}