call a function in sibling directive from another directive - Angularjs

Question

i have two directives defined inside a div.

<div>
    <address-book-picker></address-book-picker>
    <address></address>
</div>

In the address book picker directive there is a method as follows

scope.changed = function(addressBook) {
        if (addressBook) {
          scope.setAddress(addressBook.address);
        }
        // Call a function in the address directive
      };

When the function is invoked i need to call a function in the address directive. How to achieve this using AngularJS.