Vogler, Helmut Department of Organic Chemistry, Max Planck Institute for Medical Research, Max Planck Society;
http://match.pmf.kg.ac.rs/electronic_versions/Match17/match17_191-201.pdf (Any fulltext)
Vogler, H. (1985). Ring current effects in doubly and quadruply charged annulenes. Match-Communications in Mathematical and in Computer Chemistry, 17, 191-201. Retrieved from http://match.pmf.kg.ac.rs/electronic_versions/Match17/match17_191-201.pdf.