Lars Erik ("Lasse") Dahlquist (14 September 1910 in Örgryte (grew also up in Lidingö) – died 14 October 1979 on Brännö, Gothenburg archipelago due to laryngeal cancer) was a Swedish composer, singer and actor. Many of his songs are among the most popular sing-along songs in Sweden, such as Oh boy oh boy oh boy and Gå upp och pröva dina vingar. He was married to Inez Margareta Dahlquist, née Lindquist (1911–2004) from 1936 and they had a son; the saxophonist Robert "Bob" Dahlquist (2 September 1938 – 6 September 2005).
https://en.wikipedia.org/wiki/Lasse_Dahlquist