The two most popular formal systems of in-text citations are Harvard style and footnotes. Less formal system of inline citations found online include simple hyperlinks to refer to online texts.
At present, academic legal articles are always footnoted, but motions submitted to courts and court opinions traditionally use inline citations which are either separate sentences or separate clauses. Inline citation is controversial among lawyers, because it is thought to be one of the reasons why most laypersons find legal writing hard to read.