Answer:
quotes from a variety of knowledgeable experts
Step-by-step explanation:
To provide credibility for his article, the writer of this article used statements and quotations made by reliable sources. Some of these reliable sources included, Dr. Christopher Giza, Dr. Frederick Rivara, Dr. Beth Ansel, Dr. Keith Yeates, etc.
The use of these experts in the medical field instills confidence in the readers because these group of people must have knowledge and experience in dealing with brain concussions, therefore, whatever advise and suggestions they have to give about it can be considered as reliable and true.