Reference

A.R. Al-Khazzar, M.J. Earnshaw, R.D. Butler, M.J. Emes, D.C. Sigee (1984): Tentacle contraction in Discophrya collini: The effects of ionophore A 23187 and ruthenium red on Ca2+-induced contraction and uptake of extracellular calcium – Protoplasma – 122: 125 - 131.