Based on a sample of German innovating firms that contains information on formal and informal innovation cooperation between customers and suppliers, we state that firms perceive informal cooperation as being more important than formal cooperation modes. We then investigate the determinants of...

The neoclassical model of the production function, as applied by Robert Solow to build the neoclassical model of growth, linked labor and capital to output. More recently, Romer and others have expanded the model to include measures of knowledge capital. In this paper we introduce a new factor,...