Most journals have their own standards. Some follow the main standards (e.g. APA, Chicago, Harvard), some use variations of these (e.g. whether in the list of References, authors' first names should or should not be included, what should be in Italics..). Still, they expect authors to follow their guidelines; papers not following these guidelines will not be published. Thus, every time you submit your work to such a journal, you have to follow this journal's guidelines. This means that if you send your work to different journals, you have to adjust the style almost every time.