Young H.L. Summary of ground-water hydrology of the Cambrian--Ordovician aquifer system in the northern Midwest,United States / H.L.Young, 1992. - VI,55 p. p. - Текст : непосредственный.
Young H.L. Hydrogeology of the Cambrian-Ordovician aguifer system in the northern midwest,United States / H.L.Young,D.I.Siegel, 1992. - VII,B 99 p. 99 p. - Текст : непосредственный.