Wahl K.L. The stream-gaging program of the U.S.Geological survey / K.L.Wahl,W.O.Thomas,R.M.Hirsch, 1995. - IV,22 p. p. - Текст : непосредственный.
Wahl K.L. Precipitation on the upper Mississippi River Basin,Jan.1-through July 31,1993 : Floods in the Upper Mississippi River Basin / K.L.Wahl,K.C.Vining,G.J.Wiche, 1993. - 13 p. - Текст : непосредственный.