* Livingood, J.; Seaborg, G. (1938). «Long-Lived Radio Cobalt Isotopes». Physical Review 53 (10): 847. Bibcode:1938PhRv...53..847L | * Livingood, J.; Seaborg, G. (1938). «Long-Lived Radio Cobalt Isotopes». Physical Review 53 (10): 847. Bibcode:1938PhRv...53..847L |