%0 Journal Article %A Ryuji Sasaki %A Keisuke Toki %T Determination of Fermat varieties with trivial Hasse-Witt map (an application of the Farey series) %J Acta Arithmetica %D 1991 %P 381-401 %V 59 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/aa-59-4-381-401/ %R 10.4064/aa-59-4-381-401 %G en %F 10_4064_aa_59_4_381_401