Kudrik EV, Makarov SV, Zahi A, van Eldik R. Kinetics and mechanism of the cobalt phthalocyanine catalyzed reduction of nitrite and nitrate by dithionite in aqueous solution. Inorg Chem. 2003 Jan 27;42(2):618–24. doi: 10.1021/ic020290f. PMID: 12693247.