https://webbook.nist.gov/cgi/inchi?ID=C822355&Units=SI&Mask=1
Cyclobutene
https://research.ibm.com/publications/high-vibrational-overtone-photochemistry-of-cyclobutene
High vibrational overtone photochemistry of cyclobutene for The Journal of Chemical Physics - IBM...
High vibrational overtone photochemistry of cyclobutene for The Journal of Chemical Physics by Joseph M. Jasinski et al.