"It is, therefore, possible to extend a partially specified interpretation to a complete interpretation, without loss of verifiability... This fact offers the possibility of automatic verification of programs, the programmer merely tagging entrances and one edge in each innermost loop."
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Source : "Assigning Meanings to Programs" by Robert W. Floyd, published in "Proceedings of Symposium on Applied Mathematics", Volume 19 (p. 25), 1967.
Source : Barack Obama's Remarks at Congressional Black Caucus Foundation Annual Phoenix Awards Dinner, obamawhitehouse.archives.gov. September 24, 2011.