I am currently looking for a reference that covers the Penrose-Ward transformation. For context the Penrose-Ward transformation relates a holomorphic vector bundle $E$ on some twistor space $Z$, with Kodaira moduli space $M$, to a holomorphic vector bundle with holomorphic connection on $M$ provided the bundle $E$ is $M$-trivial. At the moment one of my references for this is "The generalized Penrose-Ward transform" by M. Eastwood. And the other is "Gauge Field Theory and Complex Geometry" by Y. Manin.
I am interested in a reference that is more detailed than "The generalized Penrose-Ward transform" and also a reference that covers the Penrose-Ward transformation in the case where the vector bundle $E\to M$ comes from an instanton. The second point is only commented on in "Gauge Field Theory and Complex Geometry" after Theorem 11 in Chapter 2 §2.
To summarize, I am looking for a detailed introduction to the Penrose-Ward transform that explains how to recover the self-dual connection from the holomorphic connection.