I just started using Stanford Parser but I do not understand the tags very well. This might be a stupid question to ask but can anyone tell me what does the SBARQ and SQ tags represent and where can I find a complete list for them? I know how the Penn Treebank looks like but these are slightly different. 

```
Sentence: What is the highest waterfall in the United States ?

(ROOT
  (SBARQ
    (WHNP (WP What))
    (SQ (VBZ is)
      (NP
        (NP (DT the) (JJS highest) (NN waterfall))
        (PP (IN in)
          (NP (DT the) (NNP United) (NNPS States)))))
    (. ?)))

```

I have looked at Stanford Parser website and read a few of the journals listed there but there are no explanation of the tags mentioned earlier. I found a manual describing all the dependencies used but it doesn't explain what I am looking for. Thanks!