References. It is assumed that you have references if you have previous employment history. It is not at all necessary to include “references available upon request”, adding this is actually a potential deterrent. Potential employers will ask you for your references later on in the interview process if they see fit. Of course, if references are asked for within the application process, provide them - just not on your resume.
Ultimately, you want to try to strike a balance between including experience that is both timely and relevant. There are several basic types of resumes used to apply for job openings. Before you spend time writing up all the details around each position you’ve had, you should decide what style of resume to use, as that can affect how you describe, organize, and list your experience, education, skills, qualifications, and other credentials for employment.