Toktok (Pep #35, 1975)
Peter Coolen was born in Eindhoven. He followed a mail course at the Famous Artists School, and worked for a while as a ceramics artist, art painter and freelance advertising artist. He entered the comics field after meeting Uco Egmond in 1970s.
De Leukebroeders (Eppo #4, 1984)
He made the stop-comic 'Toktok' in Pep and Eppo between 1975 and 1980. Under the collecte pseudonym Peco, Coolen and Egmond created the series 'De Leukebroeders' in 1976. Coolen has also done advertising comics.