I have joined a Marathi group here in the Bay Area that plans to read Jñāneśvara's Amr̥tānubhava.  The very first verse salutes Nivr̥ttinātha as his Guru.  I have tried to locate compositions of Nivr̥ttinātha himself, without any success so far.  I would appreciate any help on sources, and also on the connection of Nivr̥ttinātha to the Nātha tradition, and the connection of the Nātha tradition to Kashmiri Shavism.  With best wishes,