Italy: Ala Littoria airmail labels

Here are the labels issued by Ala Littoria airlines, Italy.

Year: 1.7.1937, Gummed. Günter Mair's catalogue no: - ITA-B-17, rouletted (looking like perforated
13 ¼ ), sheets of 20(2x10) or booklets of 2,3 or 4 sheets of 4(2x2), dark blue or blue/white, 4****

Year: 1935, Gummed. Günter Mair's catalogue no: - ITA-B-15, perforated 10 ¾ , sheets of 10(2x5) or
18(2x9), dark violet-blue or dark grey-blue or dark blue or light ultramarine/white, 4****

Year: 1939, Gummed. Günter Mair's catalogue no: - ITA-B-22, perforated H 11 ½ , V 10 ½ , sheets,
Issued for customers in Egypt, grey-blue or blue/white, 4****