xpath - condition expression

Question

I have the below document:

<Ships>
   <Class name = "Kongo" >
        <Ship name "Kongo" launched = "1913" />
        <Ship name = "Hiei" launched = "1914"/>
        <Ship name = "Haruna" launched = "1915" />
   </Class>
   <Class name = "North Carolina">
        <Ship name = "Washington" launched= "1941"/>
   </Class>
</Ships>

I need to find the years in which ships having the same name as their class were launched. Which should be

/Ships/Class/Ship[..]/@launched

the '...' part has been omitted as it should be a condition that specifies where the ship name equals to its class name. Does anyone know how to refer to a higher level element's attribute? The query should return '1913'

Answer 1

Ships/Class/Ship[@name = ../@name]/@launched