Title: Kahl's keys to the ciliates
Subtitle: a translation by D.J. Patterson of the keys to the level of subgenus, originally published in Kahl, A., 'Wimpertierre oder Ciliata', in Dahl's 'Die Tierwelt Deutschlands', parts 18 (1930), 21 (1931), 25 (1932) and 30 (1935).
First published: 1978