Assertion: canker sore's center | /r/HasProperty | white
Facets:
Source sentences:
text: They often have a white or yellowish center.
text: In general, canker sores tend to stick around for a week before they show any signs of healing and at in its earliest stages, the center of the canker sore will be white but slowly fade to grey as it heals.
text: They are small in appearance, round or oval, and have a white or yellow center and a red border.