Seaborg, Glenn T.; Perlman, Morris L. (1948). "Search for Elements 94 and 93 in Nature. Presence of 94239 in Pitchblende1". Journal of the American Chemical Society. 70 (4). American Chemical Society (ACS): 1571–1573. doi:10.1021/ja01184a083. ISSN0002-7863.
Seaborg, Glenn T.; Perlman, Morris L. (1948). "Search for Elements 94 and 93 in Nature. Presence of 94239 in Pitchblende1". Journal of the American Chemical Society. 70 (4). American Chemical Society (ACS): 1571–1573. doi:10.1021/ja01184a083. ISSN0002-7863.