https://www.thevespiary.org/rhodium/Rhodium/chemistry/tcboe/references.html (https://www.thevespiary.org/rhodium/Rhodium/chemistry/tcboe/references.html)
Patent US1313192 (http://l2.espacenet.com/dips/viewer?PN=US1313192&CY=gb&LG=en&DB=EPD)