1. Bent, H.: New Ideas in Chemistry from Fresh Energy for the Periodic Law. Authorhouse, Bloomington (2006)
2. Biltz, W.: Raumchemie der festen stoffe, S. 197. L. Voss, Leipzig (1934)
3. Biron, E.V.: Phenomena of secondary periodicity. Zh. Russ. Fiz.-Khim. Obshch. Ch. Khim. 47, 964–988 (1915). (in Russian)
4. Blagojevic, V., Lavrov, V.V., Koyanagi, G.K., Bohme, D.K.: Early atomic transition metal cations reacting with ammonia at room temperature: H2 elimination and NH3 ligation kinetics across and down the periodic table. Int. J. Mass Spect. 435, 181–187 (2019)
5. Filippov, G.G., Gorbunov, A.I.: Four ‘“correct”’ forms of the periodic system of elements. Zh. Fiz. Khim. 67, 1809–1812 (1993). (in Russian)