I know it must have been uploaded sometime before now by someone, but it is more important that the uploaded file downloads properly(like yours did) and not just some piece of jumbled algorithm that comes up with an error message. Thank you very much for the upload, nice one. Could you happen to have some other oil and gas based past questions in your possession? Would really appreciate it if you put them through the same beautiful process through which you've put this PTDF past question.