Ostwald, Wilhelm, "Improvements in the Manufacture of Nitric Acid and Nitrogen Oxides", GB 190200698, publicada 9 gener 1902, emesa 20 març 1902
Ostwald, Wilhelm, "Improvements in and relating to the Manufacture of Nitric Acid and Oxides of Nitrogen", GB 190208300, publicada 18 desembre 1902, emesa 26 febrer 1903