National performance audit program : 1980 proficiency surveys for sulfur dioxide, nitrogen dioxide, carbon monoxide, sulfate, nitrate, lead and high volume flow /

Mode of access: Internet.

Report of preliminary investigations on the metabolism of nitrogen and carbon in the human organism, with a respiration calorimeter of special construction.

Mode of access: Internet.

Nitrogen and carbon changes in Great Plains soils as influenced by cropping and soil treatments /

Chiefly tables.