Freitas, Tracey Allen K.; Saito, Jennifer A.; Wan, Xuehua; Hou, Shaobin; Alam, Maqsudul (2008), "Protoglobin and Globin-coupled Sensors", The Smallest Biomolecules: Diatomics and their Interactions with Heme Proteins, Elsevier, pp. 175–202, doi:10.1016/b978-044452839-1.50008-5, ISBN9780444528391