%0 Journal Article %A L. Mordell %T The Diophantine equation $x^4 + y^4 = 1$ in algebraic number fields %J Acta Arithmetica %D 1968 %P 347-355 %V 14 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/aa-14-4-347-355/ %R 10.4064/aa-14-4-347-355 %G en %F 10_4064_aa_14_4_347_355