According to PHPdoc.org, you could use the @see tag for that.
/**
* @see http://example.com/my/bar Documentation of Foo.
* @see MyClass::$items For the property whose items are counted.
* @see MyClass::setItems() To set the items for this collection.
*
* @return integer Indicates the number of items.
*/
function count()
{
<...>
}
Also, PHPdoc.org recommends to use @see in case of a @deprecated method:
It is RECOMMENDED (but not required) to provide an additional description stating why the associated element is deprecated. If it is superceded by another method it is RECOMMENDED to add a @see tag in the same PHPDoc pointing to the new element.
But @see
is not always required, for example "Link to another method in @param tag's description?"