. "A series of molecular signals in which a cell uses calcium ions imported from an extracellular source to convert a signal into a response." . . "calcium-mediated signaling using extracellular calcium source" . "calcium signaling using extracellular calcium source" . "calcium signalling using extracellular calcium source" . "calcium-mediated signalling using extracellular calcium source" . "extracellular calcium influx" . .