Denmark: Airmail labels

Here are an old airmail labels from Denmark.

Year: 13.4.1926, Gummed. Günter Mair's catalogue no: - DNK-A-1, perforated 11 ½ , sheets of 
10(2x5), ref.: "F Form. Nr. 63 (13/4 26), black/light yellow, 4****

Year: 1.1.1928, Gummed. Günter Mair's catalogue no: - DNK-A-2a, perforated 11, (but all my labels 
are perforated 10 ¾ , sheets of 10(2x5), label in upper right position comes with 
ref.: F.Form.Nr.63 (⅟1 28)", dark blue or black-blue or blue or grey-blue/white, 3***

Unlisted color variety: violet-blue-grey?

Year: 12.1934, Gummed. Günter Mair's catalogue no: - DNK-A-3, perforated 11 or 10 ¾ , sheets of 10(2x5), label in lower position comes with ref.: F.63 12/34.", turquoise blue/white, 3***