Rutherford y Soddy, Phil. Mag. abril de 1903.

Rutherford, Phil. Trans. A. p. 169, 1904. Curie y Danne, C. R. p. 748, 1904.

P. Curie y Danne, Comptes Rendus, 138, p. 748, 1904.

Miss Gates, Phys. Rev. p. 300, 1903.

Miss Brooks, Nature, 21 de julio de 1904.

Rutherford, Phil. Mag. Nov. 1904. Nature, p. 341, Feb. 9, 1905.

Rutherford, Nature, p. 341, 9 de feb. de 1905.

Marckwald (Ber. d. D. Chem. Ges. p. 591, 1905) has recently found that the activity of his radio-tellurium falls to half value in 139 days.

Meyer y Schweidler, Wien Ber. 1 de dic. de 1904.

Rutherford, Phil. Trans. A. p. 169, 1904.

Hofmann, Gonder y Wölfl, Annal. d. Phys. 15, p. 615, 1904.

Phil. Trans. A. p. 25, 1901.

P. Curie y Laborde, C. R. 136, p. 673, 1903.