↑Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements (New izd.). New York, NY: Oxford University Press. str. 278–9. ISBN978-0-19-960563-7.
↑Gyanchandani, Jyoti; Sikka, S. K. (10. maj 2011). »Physical properties of the 6 d -series elements from density functional theory: Close similarity to lighter transition metals«. Physical Review B. 83 (17): 172101. doi:10.1103/PhysRevB.83.172101. {{navedi časopis}}: |access-date= potrebuje |url= (pomoč)
↑Brown, Geoffrey (2012). The Inaccessible Earth: An integrated view to its structure and composition. Springer Science & Business Media. str. 88. ISBN9789401115162.