References
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- Doolittle , R. E. and Bradsher , C. K. 1966 . J. Org. Chem. , 31 : 2616 see also : E. V. Blackburn and C. J. Timmons, Quart. Revs., 23, 482 (1969)
- Badger , G. M. , Joshua , C. P. and Lewis , G. E. 1964 . Tetrahedron Letters , : 3711
- Häft , E. , Rieche , A. and Schültze , H. 1966 . Ann. , 697 : 181