2. The Geometry of Porphyrin: A Fourfold Mandala
• Gouterman, M. (1961). Spectra of porphyrins. Journal of Molecular Spectroscopy, 6(1), 138–163. https://doi.org/10.1016/0022-2852(61)90236-3
Gouterman’s work provides foundational insight into the spectral properties of porphyrins, relating their geometry ...
very good