1. Mittasch A (1950) Adv Catal 2: 81.
2. Mittasch A (1951) Geschichte der Ammoniak Synthese Verlag Chemie Weinheim.
3. Nielsen A (1953) Adv Catal 5: 1.
4. Bokhoven C, Van Herden C, Westrik R, Zwietering P (1955) In: Emmett P (ed) Catalysis, Vol 3 p 265.
5. Frankenburg W (1955) In: Emmett PH (ed) Catalysis, Vol 3 p 171.