1. K.L. Waters, Chem. Rev. 41, 585 (1947).
2. J. Plochl, Ber. 2815 (1883).
3. J. Buck and W. Ide, Organic Syntheses vn2, 11, 1949.
4. H. Snyder, J. Buck and W. Ide, Organic Syntheses 2, 164, 1949.
5. A. Ellinger and Z. Matzuoka, Z. Physiol. Chem. 109, 259 (1920).