Assertion: vitamin e's form | /r/HasProperty | pure
Facets:
Source sentences:
text: Vitamin E was discovered in 1922 by Herbert McLean Evans and Katharine Scott Bishop and first isolated in a pure form by Evans and Gladys Anderson Emerson in 1935 at the University of California, Berkeley.
text: Vitamin E, first recognized in 1922, was first obtained in a pure form in 1936; it was identified chemically in 1938.