4-Thia-1-azabicyclo03.2.0)heptane-2-carboxylic acid, 6-0(aminophenylacetyl)amino)-3,3-dimethyl-7-oxo-, 02S-02alpha,5alpha,6beta(S*)))-, mixt. with (2S-cis)-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo03.2.0)heptane-2-carboxylic acid 4,4-dioxide