Bauer, Helmut Department of Organic Chemistry, Max Planck Institute for Medical Research, Max Planck Society;
http://onlinelibrary.wiley.com/doi/10.1002/ange.19680801812/epdf (Any fulltext)
https://doi.org/10.1002/ange.19680801812 (Any fulltext)
Bauer, H. (1968). Tetramethyl-pyrrol-indigo. Angewandte Chemie, 80(18), 758. doi:10.1002/ange.19680801812.