Göttingen: Vandenhoeck & Ruprecht, 1975. — xiii, 226 S. — (Ergänzungshefte zur Zeitschrift für vergleichende Sprachforschung, Nr. 24). — ISBN: 9783525262115.
Hauri asks himself: "From what verbs, and at what time, were asigmatic or sigmatic futures formed, and what factors possibly influenced the choice of the one or the other formation?" His corpus of material is restricted to verbs with aorists in short vowel plus -s-, since liquid/nasal verbs always have an asigmatic future. Part one contains the corpus organized by vowel (-asa, -esa, -osa, -ysa, -isa), within vowel by derivational type, and within derivational type by shape of the stem. Part two summarizes the data of part one, and presents conclusions.