According to multiple sources (1 and 2), the word "contra" can be employed as either a preposition or an adverb. From my perspective, however, there is a dearth of clear examples featuring this word in context. I am looking for input on its general usage, in addition to whether or not "contra" can/should be used in conjunction with "to," a la "contrary to," "counter to," etc.
It is widely used in legal English (well, Italian in my case...). If you're discussing a law topic, you usually cite a number of decisions or some author's opinion to support a point, to make a case for it. But other decisions might have ruled against that principle, or other authors might disagree with it, and in that case you would write "Contra" followed by the citation.