1. Äbro, A.: Cytological observations on spermiogenesis in Drosophila melanogaster Meigen. Acta Universitatis Bergensis. Series Mathematics Rerumque Naturalium 6, 1?23 (1964a).
2. ?: On the synchronous differentiation of spermatogenic cells in Drosophila melanogaster Meigen. Acta Universitatis Bergensis. Series Mathematica Rerumque Naturalium 1, 3?16 (1964b).
3. Anderson, W.A.: Cytodifferentiation of spermatozoa in Drosophila melanogaster: the effect of elevated temperature on spermiogenesis. Molec. gen. Genet. 99, 257?273 (1967).
4. Baccetti, B., Bairati, A.: Indagini comparative sull'ultrastruttura delle cellule germinali maschili in Dacus oleae Gmel. ed. in Drosophila melanogaster Meig. (Ins. Diptera). Redia 49, 1?29 (1964).
5. Bairati, A.: Struttura ed ultrastruttura dell'apparato genitale maschile di Drosophila melanogaster Meig. I. Il testicolo. Z. Zellforsch. 76, 56?99 (1967).