Reference

J.A. Van Bruggen, K.B. Zwart, R.M. van Assema, C.K. Stumm, G.D. Vogels (1984): Methanobacterium formicicum, an endosymbiont of the anaerobic ciliate Metopus striatus McMurrich – Arch. Mikrobiol. – 139: 1 - 7.