Greece: Airmail labels 5

Here are rare airmail labels from Greece. The label design looks similar to some of french colonies labels.

Year: approx.1955, Ungummed. Günter Mair's catalogue no: - GRC-C-2a, imperforated, sheets, 
black/light grey-blue, 4****

Year:  approx.1955, Ungummed. Günter Mair's catalogue no: - GRC-C-2b, imperforated, sheets, 
black/light yellow, 4****