Sentence examples for occurrence is doubtful from inspiring English sources

Diploid A. neglecta was described mainly from the Carpathians and rarely from the Alps, where its occurrence is doubtful, since in the Alps this taxon was referred to as Cardaminopsis arenosa var.

Finally, the hypothesis of uniform occurrence of CNA is doubtful and some of the platforms have been designed to provide non-uniform coverage by tiling more probes in known regions of variation (see Methods section for further details), or in areas where variation would be of particular interest.

It is doubtful that the occurrence of the nutritional problems described among the older relatives in this study can be explained as their making a deliberate choice to shorten their life.

That much is doubtful.

Mr Piketty is doubtful.

Danny Welbeck (muscle) is doubtful.

Fontana is doubtful.

But Twagirimana is doubtful.

However it is doubtful.

A glutton, Antony is doubtful.

David Torrance, Alex Salmond's biographer, is doubtful.