It's been very difficult to establish "common ground" across the dispatch box, he says.
But who provided what to whom, this is very difficult to establish".
"Now you'd find it very difficult to establish a reasonable book on Nicola's successor".
"It is something that's very difficult to establish systematically," said Professor Berger.
"Those kinds of relationships are very, very difficult to establish, and sometimes it takes years to establish," Mr. Baker said.
In all retail, the secret of success is repeat business, which is very difficult to establish with trend-conscious buyers.
At a news conference, Dr. Garcia said the concept of an event horizon at black holes was "well grounded in theory but observationally very difficult to establish".
For juries, it becomes very difficult to establish value and thus what kind of crime was committed, or even if one was committed at all.
It was one of a line of examples where the Reynolds defence has proved very difficult to establish when it relying on unidentified sources.
Having an array of painting of widely varied standards is liberating, he said, adding that it would have been very difficult to establish criteria for inclusion.
Though it was immediately suspected, following Röntgen's discovery, that X-rays were a form of electromagnetic radiation, this proved very difficult to establish.
