Staab, Heinz A. Department of Organic Chemistry, Max Planck Institute for Medical Research, Max Planck Society;
http://www.sciencedirect.com/science/article/pii/S0040403900744078/pdf?md5=b7b7272d45b6adf8bf07b64454660d3a&pid=1-s2.0-S0040403900744078-main.pdf (beliebiger Volltext)
https://doi.org/10.1016/S0040-4039(00)74407-8 (beliebiger Volltext)
Rentzea, M., Diehm, M., & Staab, H. A. (1994). Cyclization of diaza[6]helicenes to monoazacoronenes under electron impact. Tetrahedron Letters, 35(45), 8361-8364. doi:10.1016/S0040-4039(00)74407-8.