O'Connor, H. G. (1960). Geology and ground-water resources of Douglas County, Kansas. s.n.].
Citazione stile Chigago Style (17a edizione)O'Connor, Howard G. Geology and Ground-water Resources of Douglas County, Kansas. [Lawrence: s.n.], 1960.
Citatione MLA (9a ed.)O'Connor, Howard G. Geology and Ground-water Resources of Douglas County, Kansas. s.n.], 1960.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.