A one-stop source about multigenerational homes, ADU's, granny flats, backyard cottages, in-law units, accessory dwelling units…
Link to Appraisal Journal paper published 2012: Understanding and Appraising Properties with Accessory Dwelling Units.
Executive Summary of an earlier presentation::
Guidance related to appraising properties with permitted ADUs:
Example of permitted ADU appraisal: