This is N. dubius as I know it. This specimen is a bit mite damaged. I have not seen one that I would describe as yellow but I have felt that some have a reversish look about them. It is cold and frosty when they flower here. It strikes me that the yellow might burn out more quickly in warmer places. It is damaged by heavy frosts here in the field and is a marginal plant.
Certainly looks like it except for the creamy color in the fresh flower, but the leaves do seem to be more prostrate. N. dubius occurs over a wide area on the eastern side of Spain and into southern France so there could be populations with different characteristics.
Harold