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My time is extremely short, and therefore I simply have to express myself in a somewhat categorical form, although the aim of my speech is not the proclamation of dogmatic truths but the marking out of some approaches and problems which seem to me of special interest for our study. No doubt I shall have to state my own point of view in a coherent way; some of my audience may regard my expose' as not taking possible other points of view enough into account, but I beg them to consider this as being due to the form of my presentation only. I am fully aware of the fact that other opinions do and cannot fail to exist, and of course I do not think that my results are in any way final.
I. M. Diakonoff (1975) studied this question.