Assertion: astatine | /r/CreatedBy | kenneth ross mackenzie
Facets:
value: in 1940
type: TEMPORAL
Source sentences:
text: Astatine was first produced by Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè in 1940.
text: Astatine was first produced by Dale R. Corson, Kenneth Ross MacKenzie, and Emilio Segrè in the University of California, Berkeley in 1940.