Found:

definiteness restriction

SYNTAX/SEMANTICS: the restriction that the subject of a sentence beginning with expletive there, must be an indefinite noun phrase, or in Milsark's (1977) terms, a weak noun phrase. The definiteness restriction is shown by the contrast between (i) and (ii): the strong noun phrases in (i) are not compatible with expletive there.

(i)   a	*There is John/the man/every man in the room
      b	*There are they/the people/most people in the room
(ii)  a	 There is a man/one man in the room
      b	 There are men/two men/many men in the room