There are several styles of referencing. Different referencing and citation styles have developed to address the specific needs of disciplines. All reference styles tend to include similar elements, such as the title, author, and date, but they have different formatting conventions (i.e., the order of the elements, capitalization, etc.) to those familiar with that specific style.
Publishers developed rules of style for specific manuscript structure, punctuation, graphics, and references to move an idea forward to achieve clarity of communication of that field. It may seem like academic entities can't agree, but authors write for different purposes and different audiences, so the citation styles reflect that. We continue to use different citation styles for two reasons: disciplinary differences and tradition.