1. A computer-aided method to determine whether an unidentified author of a textual work belongs to a group comprising the textual work of a known author, the method comprising the steps of: obtaining a sample of the textual work of the unidentified author; obtaining a sample of the textual work of the known author; entering the samples into a computer system, the computer system including a memory, a means for analyzing documents, and a means for determining belonging, stored within the memory; utilizing the means for analyzing documents, splitting the entered samples into individual sentences, the sentences each including a head, a plurality of words and punctuation, the punctuation defining a syntactic edge within the individual sentence, and graphemic features defining a discursive function emphatic selected from the group consisting of: bolding, italics, capitalization, emoticons and serial punctuation marks; categorizing the punctuation by determining the syntactic edge; indicating the discursive function emphatic, a graphemic feature being generated by the steps of categorizing and indicating; dividing each of the individual sentences into the words; labeling each of the words as a part of speech; listing the labeled words into phrases for each labeled word; identifying phrases for each said head; classifying the identified phrases as marked or unmarked; characterizing the identified phrases by markedness, thereby producing a plurality of syntactic features; and utilizing the means for determining belonging, inputting at least one of the syntactic features and inputting at least one feature selected from the group consisting of: (i) the graphemic features and (ii) the syntactic edges defined by punctuation; wherein the inputting is done for each said sample to determine whether the unidentified author of the textual work sample belongs to the known author group.