BTW. Summer time

"Summertime" is the name of an aria composed by George Gershwin for the 1935 opera Porgy and Bess. The lyrics are by DuBose Heyward. The song soon became a popular jazz standard.

Gershwin is said to have based this song on a Ukrainian lullaby, Oi Khodyt Son Kolo Vikon (A Dream Passes By The Windows), which he heard in a New York City performance by Oleksander Koshetz’s Ukrainian National Chorus.

(from wikipedia)