Stanford Parser tags

Question

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!

Answer 1

This reference looks to have an extensive list - not sure if it is complete or not.

Specifically, it lists the ones you're asking about as:

SBARQ - Direct question introduced by a wh-word or a wh-phrase. Indirect 
        questions and relative clauses should be bracketed as SBAR, not SBARQ.
SQ    - Inverted yes/no question, or main clause of a wh-question, 
        following the wh-phrase in SBARQ.