1. A. Arnaud, Compt. rend., 106, 1011 (1888); Chem. Ber., 2, Referate 359 (1888).
2. A. Arnaud, Compt. rend., 107, 1162 (1889); Chem. Ber., 22, Referate 105 (1889).
3. F.E. Fraser and Tillie (1899), cited in E.S. Faust, Chem. Zentralblatt II, 886 (1903).
4. E.S. Faust, Chem. Zentralblatt II, 1217 (1902).
5. H. Thomas and C. Mannich, Chem. Zentralblatt I, 1277 (1904).