1. B. Radziszewski, Ber. Dtsch. Chem. Ges.,2, 208 (1869).
2. R. Shteiger, Synthesis of Organic Preparations Vol. 3 [in Russian], Moscow (1952), p. 63.
3. F. Tiemann, Ber, Dtsch. Chem. Ges.,13, 383 (1880).
4. A. Ulrich, Ibid.,37, 1688 (1904).
5. I. Zelinskii and G. Stadnikov, Zh. Russk. Khim. Obsh.,38, 473 (1906).