Wim Hessels, who signs with Woeloem, was born in Wormer and studied at the Hendrik de Keyserschool in Amsterdam. He is known for his comics for little children, and was a frequent contributor to Okki magazine in the 1960s and 1970s. He made comics like 'Stoffertje Zuig' (1967-68), 'Manusje van Alles' (1968-70), 'Boerensloot' (1970-72) and 'Spatje' (1977-78). For the monthly Dierenbescherming, he made 'Muisje Nisje' in 1977-78. He was also present in Taptoe with 'Pas op voor Vopium' (1976).