A reference from a person who can vouch for your qualifications for a job. A professional reference is typically a former employer, a colleague, client, vendor, supervisor, or someone else who can recommend you for employment and not your friends or anyone from your family. So you need to add people who have good experience such as team manager, HR, Product managers, etc. The reference should know you in and out to refer to a job that will improve your chances of cracking the job.