Papers from an unlabelled folder. Material relates to ZK publications from the early 1980s.
- Eds. Z. Kopal and Jügen Rahe. Binary and Multiple Stars as Tracers of Stellar Evolution. Proceedings of a colloquium, Bamberg, Germany, August 1981. 1982. Boston/USA: D. Reidel Publishing Company.
- Eds. Ellen B. Carling and Z. Kopal. Photometric and Spectroscopic Binary Systems. 1981. Dordrecht/Holland: D. Reidel Publishing Company.