%0 Journal Article %A R. P. Gilbert %T Harmonic functions in four variables with rational and algebraic $p_4$-associates %J Annales Polonici Mathematici %D 1964 %P 273-287 %V 15 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/ap-15-3-273-287/ %R 10.4064/ap-15-3-273-287 %G en %F 10_4064_ap_15_3_273_287