I would like to cite
The United States of America v. Otto Ohlendorf et al: Opinion and Judgment and Sentence’, Military Tribunal, No. 2, 9 April 1948
I am not sure the right way to do this. I assume it is not a journal but I am not sure what sort of publication it is.
It exists online as well.
The point of a citation is not to satisfy some abstract administrator who is intent on making sure that rules are followed, but to make it possible for a reader to find the work you are referencing.
So, if the style you are using does not have a specified way to reference what you want to reference, then make something up. The guideline to follow is: Does however you provide the reference make it possible and easy for your reader to identify which document you are referencing?
I suspect none of the standard bibliographic guidelines or packages have an entry for this (I assume you checked). So invent something that provides the information your reader would need to find the reference for themselves. When your paper is accepted for publication an editor will make the final formatting decision.
