How can these classes be associated?

I am having a Taxi that transports Person and this Transportation is covered by an Agreement. How can these 4 classes be associated in a UML Diagram?

I have tried to associate Person and Taxi. But how can I show that this is a Transportation that is then covered by the Agreement?

Solution

You could use an association class called Transportation for the Taxi-Person association. Agreement could be a separate class, associated with Transportation. It is allowed to associate an association class with another class.