Paul Romer's seminal paper - “Endogenous Technological Change” - was published 25 years ago:
http://www.digitopoly.org/2015/10/03/the-romer-model-turns-25/
Paul Romer on Human Capital and Knowledge
http://paulromer.net/human-capital-and-knowledge/
http://paulromer.net/human-capital-and-knowledge/