1. Hart, L. S.: Ph. D. (London) (1967).
2. Anschütz, R.: Justus Liebigs Ann. Chem., 346, 381–382 (1906).
3. Reich, D. A. and Nightingale, D. V.: J. Org. Chem., 21, 825–826 (1956).
4. Mohan, S. B.; Jhingan, A. K.; Vij, R. K.; Parthasarathi, J. and Murti, V. V. S.: Curr. Sci., 48 (9) 393–394 (1979); Chem. Abstr., 91, 107760d (1979).
5. Garazd, M. M.; Garazd, Ya. L.; Ogorodniichuk, A. S.; Shilin, V. V.; Turov, A. V. and Khilya, V. P.: Chem. Nat. Compd., 34 (4) 442–447 (1998) (Pub. 1999); Chem. Abstr., 131, 214522u (1999).