@article{10_4064_aa125_4_5,
     author = {Keiji Okano},
     title = {Abelian $p$-class field towers over the cyclotomic
 $\mathbb {Z}_p$-extensions of imaginary quadratic fields},
     journal = {Acta Arithmetica},
     pages = {363--381},
     publisher = {mathdoc},
     volume = {125},
     number = {4},
     year = {2006},
     doi = {10.4064/aa125-4-5},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa125-4-5/}
}