* [http://knol.google.com/k/jon-awbrey/differential-logic/3fkwvf69kridz/2 Differential Logic], [http://knol.google.com/ Google Knol] | * [http://knol.google.com/k/jon-awbrey/differential-logic/3fkwvf69kridz/2 Differential Logic], [http://knol.google.com/ Google Knol] |