Creating a query to get issues not associated with more than one parent link

[swiese86]

I am currently creating a query to get issues not associated with more than one parent link.  Right now I can get a return with one parent link listed:

(issuekey not in childIssuesOf("WSRSPORT-9")) AND project in ("Reporting & Communication Squad") AND "Parent Link" is not EMPTY AND resolved > endofday(-30) AND cf[16302] = "Reporting and Communication Team 1" ORDER BY resolved DESC

When I try to add another parent link to exclude, I get no return.  Is there a way to include more than one parent link succesfully?  WSRSPORT-9 is the current Parent Link.