Sezen Aksu
He composed 175 songs and represented Turkey in many European music contests. A very close friend of Turkish singer Sezen Aksu, he co-wrote and composed many of the songs she performed throughout her career, as well as arranging all of her albums. It was widely known that his death tipped Sezen Aksu into depression. She dedicated her album Düş Bahçeleri to Onno (and numerous songs on virtually all of her albums since).