The requirements of this article shall not be applicable when the regents determine that a brand or trade name article, thing, or product or proprietary service is the only one which will properly meet the needs of the University of California because the item or service is unique, available only from a sole source, or is designated to match others, used in, or furnished to, a particular installation, facility, or location. Contracts for unique products or services, or personal or professional services, shall not be made unless the regents determine that the proposed price therefor is reasonable.