Available on Project MUSE and JSTOR. Online access to Contemporary Literature is available as part of the Project MUSE collections. All back issues of Contemporary Literature beginning with Vol. 1, 1960 are available online through the JSTOR digital archive.
Many manufacturers recommend water heater anode replacement every two to four years depending on the hardness of the water that passes through the tank and the quality of the water heater lining.
Your water heater has seen 16 years of use and should be considered at the end of its life. It is always easier to schedule a replacement than do an emergency replacement. Measure the height of the tank (Floor to tank top including legs if there are any)and shop for one that height to make the install easier.