The phrase "and retained by a" is correct and usable in written English.
It can be used in contexts where you are discussing something that is kept or held by a person or entity.
Example: "The documents were signed and retained by a designated officer for future reference."
Alternatives: "and kept by a" or "and held by a".
But for the Birmingham Six, their failed appeal in 1987 had secured for them one unexpected advantage; the notebooks in their case had been retrieved before the appeal, and retained by a separate police force, Devon and Cornwall.
The hydraulic lifter comprises a cam follower that is moved up and down by contact with the cam profile, and an inner bore into which the valve lifter is closely fitted and retained by a spring clip.
KPC-2 and -3 were successfully conjugated and retained by a virulent K2 K. pneumoniae recipient isolate.
When the same request packet is received and retained by an attachment point from different routes, all of the candidate routes meet the QoS and (or) the budget requirements.
The objective of this study was to develop a model that could be used to examine how the nitrogen is trapped and retained by several elements of a sandbar in an alternate bar reach.
According to Caf regulations, once a venue has been announced and retained by both Caf and a visiting team, the organising association can only change the venue in consultation with the visiting team.
An interim prosthetic obturator was fitted and relined with silicone putty material and retained by dental clasps and a single bone screw into the midline of the remaining palatal bone.
In order for environmentally-induced plasticity to have long-term evolutionary consequences, it has to be allowed and retained by organismal homeostatic processes, have a heritable component, induce similar changes across individuals, and confer consistent fitness benefits [ 6, 9, 26]; however, studies of these requirements are rare in natural systems.
The benchmark was subsequently retained by Austria, adopted by Yugoslavia, and retained by the states that emerged after its dissolution.
C. elegans males chemotax toward hermaphrodite-secreted cues and are retained by a signal in the hermaphrodite cuticle (Simon and Sternberg. 2002; White et al. 2007; Barrios et al. 2008).
