2. A method as in claim 1 wherein: a first of said analysis algorithms is arranged to generate and compare word frequency lists and to produce a comparison result; and said predetermined algorithm includes forming from the reference corpus separate first and second parts, performing a comparison between said first and second parts in accordance with said first analysis algorithm, the resulting comparison result constituting a measure of the homogeneity of said first and second parts.
2. A method as in claim 1 wherein: a first of said analysis algorithms is arranged to generate and compare word frequency lists and to produce a comparison result; and said predetermined algorithm includes forming from the reference corpus separate first and second parts, performing a comparison between said first and second parts in accordance with said first analysis algorithm, the resulting comparison result constituting a measure of the homogeneity of said first and second parts. 3. A method as in claim 2 wherein: a second of said analysis algorithms is arranged to generate and compare word-level n-gram frequency lists and to produce a comparison result; and said predetermined algorithm includes calculating a confidence value by multiplying the said measure of the homogeneity by the total number of words of the word frequency lists generated for obtaining said measure of homogeneity, and, if this confidence value is less than a predetermined threshold, setting to substantially zero the value of the weight corresponding to said second analysis algorithm.