1. A method comprising: providing a classification scheme including two or more classes, with each class associated with one or more classified document headnotes; summarizing a legal opinion to define at least one particular document headnote; automatically generating a ranked list of two or more classes of the classification scheme, with each listed class associated with one or more classified document headnotes which are similar to the one particular document headnote; and classifying the one particular document headnote based on the ranked list of classes: wherein automatically generating a list of one or more of the classes comprises: defining one or more natural-language queries based on the particular document summary; performing one or more searches of the classified document summaries based on one or more of the queries, with one or more of the searches yielding two or more found document summaries; ranking the one or more found document summaries based on relative similarity to the particular document summary to define one or more ranked document summaries; and generating the list based on one or more of the ranked document summaries.