Neugebauer, Franz A. Department of Organic Chemistry, Max Planck Institute for Medical Research, Max Planck Society;
http://onlinelibrary.wiley.com/doi/10.1002/cber.19731060603/epdf (Any fulltext)
https://doi.org/10.1002/cber.19731060603 (Any fulltext)
Neugebauer, F. A. (1973). ESR-Untersuchungen an 1,2,4,5–Tetraazapentenylen. Chemische Berichte, 106(6), 1716-1723. doi:10.1002/cber.19731060603.