Yep. Not only this but in the sample "wd:Q9682" is a lie. wd is a namespace shortcut which is expended to an URI, and the prefix to URI mapping has to be defined as part of the query, otherwise it won't work. Notice how the sample use two of those prefixes (wd and wdt): data is segregated in different namespace that one have to search for and remember each time they want to make a query. And I mean remembering the prefix value, ie a partial URI, not the little cute prefix like wd that semweb sample always use.