The reference for the first lecture:
https://www.sciencedirect.com/science/article/abs/pii/0003491679903919
https://arxiv.org/pdf/hep-th/0603043
https://arxiv.org/pdf/1805.11143
The reference for the rest of the lectures:
https://arxiv.org/abs/hep-th/0212208
https://arxiv.org/abs/1710.03853
