Subsidiaries of multinational corporations can get knowledge from outside (like customers or local science centers) or inside (like headquarters). It was thought that using one type of source would mean not using the other. But, newer ways of organizing companies show that both can be used together. A study of over 2,000 subsidiaries in Europe found that using both internal and external sources of knowledge can be good, but using too much internal knowledge can stop using external knowledge. So, it's important for subsidiaries to balance using both types of knowledge sources to grow and learn.