1. J. J. Christensen and R. M.Izatt , Synthetic Multidentate Macrocyclic Compounds , Academic Press , 1978
2. R. Steudel , The Chemistry of Inorganic Ring Systems , Elsevier , 1992
3. Chemistry of pnictogen(iii)–nitrogen ring systems
4. Main group supramolecular chemistry
5. P. Hermann and J.Kotek , Ten-membered Rings or Larger with One or More Nitrogen Atoms , Comprehensive Heterocyclic Chemistry III , Elsevier , Oxford , 2008 , ch. 14.11