The aspects of credibility that were enhanced by Kirk's action are: accuracy and respect
What are the aspects?
By providing additional sources of information, Kirk demonstrated his commitment to accuracy and his willingness to go beyond the minimum requirements to ensure the completeness of his presentation.
Also, when he provided the additional sources, Kirk showed respect for his colleague's inquiry and her desire for further knowledge on the topic. This respect fosters a positive learning environment and reinforces Kirk's credibility as a knowledgeable and approachable presenter.