@article{CM_1979__39_1_3_0,
     author = {Gerth, III, Frank},
     title = {Upper bounds for an {Iwasawa} invariant},
     journal = {Compositio Mathematica},
     pages = {3--10},
     publisher = {Sijthoff et Noordhoff International Publishers},
     volume = {39},
     number = {1},
     year = {1979},
     mrnumber = {538999},
     zbl = {0406.12005},
     language = {en},
     url = {http://www.numdam.org/item/CM_1979__39_1_3_0/}
}