What are the two primary ways a Sadguru receives service from devotees through books?

A Sadguru is said to accept two main forms of service from devotees through literary works. The first method is by creating profound spiritual works themselves, with examples like Shri Dnyaneshwari or Shri Dasbodh. As detailed in Chapter 0, the second method involves the Sadguru having their biographies written by their devotees. These biographical texts are then used for study and devotional readings, known as Parayans, by both the author and the wider community of devotees, allowing the Sadguru to accept service from the writer and the congregation simultaneously.