APA

Ahlberg J. &. A., .The Jolly Postman or Other People's Letters. : .

Chicago

Ahlberg Janet & Alan, .The Jolly Postman or Other People's Letters. : .

Harvard

Ahlberg J. &. A., .The Jolly Postman or Other People's Letters. : .

MLA

Ahlberg Janet & Alan, .: . .