1. 1905. Trans. Roy. Soc. of S. A., October Phil. Mag. April 1906.
2. 1905. Trans. Roy. Soc. of S. A., October
3. 1906. Phil. Mag., May
4. Before the publication of this work a paper appeared in the Phys. Zeit. May 1906 by Kucěra and Mašek, who describe some experiments having the object of finding the range of the α particle of polonium and the ionization along its course.