The Harvard reference style comes in many shapes, and it is not like the APA style one style with very strict rules. Many reference styles, many journals, many departments and scientists use a reference style based on the Harvard style. Harvard is an 'author/date' system, so your in-text citation consists of author(s) and year of publication. The references in the bibliography should be arranged in alphabetic order. Reference styles based upon the Harvard style is common in humanities, history, and social sciences.