How to query standard file's properties? Google Drive SDK

My goal is to check all files which are shared BY me (whetever type or permissions).

So I need to find files which I'm the owner and has Shared property set to true, so I wrote the following code:

  var listRequest = driveService.Files.List();
           listRequest.Q = "'me' in owners and shared = 'true'";
           FileList fileList = listRequest.Execute();
           foreach (var file in fileList.Items)
               SharedByMe.Add(file);

but the part with "shared = 'true'" doesn't working. I found that custom properties can be put in query, but what about standard ones? Because downloading all files and then checking it, is obviously not an option.