The text mentions several Guru biographies. Can you identify and describe the ones that are noted as being less famous, unpublished, or different in some way?

Chapter 0 introduces several Guru biographies beyond the most prominent ones. For instance, it mentions a detailed and scholarly biography by Shri Samarth Sadguru Tembhe Swami, also known as Vasudevanand Saraswati Maharaj. However, the text states this work is not as famous as the one by Shri Saraswati Gangadhar. Another biography mentioned in Chapter 0 is by Shri Samarth Sadguru Dattatreya Maharaj of Balekundri, which is described as having not yet been printed or published. Finally, a separate work called Laghu Guru Charitra is mentioned, which is older and shorter than the Brihad Guru Charitra by Saraswati Gangadhar.