1. Berger, H. (1999). Monograph of the Oxytrichidae (Ciliophora, Hypotrichia). In: Monographiae Biologicae. Dordrecht: Springer. 1–1080.
2. Berger, H. (2011). Monograph of the Gonostomatidae and Kahliellidae (Ciliophora, Hypotricha). In: Monographiae Biologicae. Dordrecht: Springer. 1–741.
3. Berger, H., Foissner, W., and Adam, H. (1985). Morphological variation and comparative analysis of morphogenesis in Parakahliella macrostoma (Foissner, 1982) nov. gen. and Histriculus muscorum (Kahl, 1932) (Ciliophora, Hypotrichida). Protistologica 21, 295–311.
4. Berger, H., and Foissner, W. (1997). Cladistic relationships and generic characterization of oxytrichid hypotrichs (Protozoa, Ciliophora). Archiv für Protistenkunde 148, 125–155.
5. Bharti, D., Kumar, S., and La Terza, A. (2015). Two gonostomatid ciliates from the soil of Lombardia, Italy; including note on the soil mapping project. J Eukaryot Microbiol 62, 762–772.