Audio source separation is the task of estimating the individual signals of several sound sources when only their mixture can be observed. State-of-the-art performance for musical mixtures is achieved by Deep Neural Networks (DNN) trained in a supervised way. They require large and diverse datasets of mixtures along with the target source signals in isolation. However, it is difficult and costly to obtain such datasets because music recordings are subject to copyright restrictions and isolated instrument recordings may not always exist.In this dissertation, we explore the usage of additional information for deep learning based source separation in order to overcome data limitations.First, we focus on a supervised setting with only a small a...