Does the Shri Sai Satcharita's preface mention other Sadgurus, or does it exclusively focus on Sai Baba?

The preface of the Shri Sai Satcharita holds other great figures in high esteem, most notably Dnyaneshwar Maharaj. In Chapter 0, the author refers to him as 'Lord Samarth Sadguru Dnyaneshwar Maharaj' and quotes his work, the Dnyaneshwari, at length to explain the importance of serving a Guru. This demonstrates deep reverence. However, the preface also distinguishes between different types of Guru service. It explains in Chapter 0 that while writing biographies of many saints yields spiritual fruit, the 'best and most certain' path is to focus on one's own Sadguru. Thus, while acknowledging others, the book's purpose is to be a detailed biography of Sai Baba.