Reconstruction of B{sup o} {yields} J/{psi}K{sup o}{und s} and measurement of ratios of branching ratios involving B {yields} J/{psi}K{sup *} and B{sup +} {yields} J/{psi}K{sup +}.

We report on the reconstruction of the decay mode B{sup 0o} {yields} J/{psi}K{sup 0}{sub s} using 19.3 pb{sup -1} of data collected by the Collider Detector at Fermilab in p{bar p} collisions at sqrt[s] = 1.8 TeV. A signal of 41.8{+-}6.9 events, with a signal-to-background ratio of 9:1, is observed. Three additional decay modes B{sup +} {yields} J/{psi}K{sup +}, B{sup 0} {yields} J/{psi}K{sup *}(892){sup 0}, and B{sup +} {yields} J/{psi}K{sup *}(892){sup +} are reconstructed. We measure three ratios of branching ratios, each one relative to the B{sup +} {yields} J/{psi}K{sup +} mode. We also report the ratio of decay rates, {gamma}(B {yields} J/{psi}K{sup *})/{gamma}(B {yields} J/{psi}K), for the vector-vector relative to the vector-pseudoscalar modes, to be 1.32{+-}0.23(stat){+-}0.16(syst).