X-ray-diffraction Analysis of New Ring-enlargement Derivatives of Penicillin G-2-thia-3,3-dimethyl-4r-(tert-butyloxycarbonylmethylene)carboxylate-5,7-diaza-6-oxo-8r-phenylacetamido-bicyclo-1r-[3,3,0]octane and 2-thia-3,3-dimethyl-4r-(tert-butyloxycarbonylmethylene)carboxylate-5,7-diaza-6-oxo-7-benzoyl-8r-phenylacetamido-bicyclo-1r-[3,3,0]octanea
(1986) Societes Chimiques Belges. Bulletin — Vol. 95, n° 4, p. 241-245 (1986)
