Find all forms/fields containing a lookup field related to a specific form

Find all forms/fields containing a lookup field related to a specific form

Hi,

I'm trying to find all forms and the specific lookup fields they contain that are related to my Contacts form. I need to be able to do this programmatically (I know how to find this information using the schema builder).  I've pulled the metadata for the forms and each form's fields but the field metadata for lookup fields does not tell you the form it is referencing:
{ "is_lookup_field": true, "unique": false, "display_name": "Lookup", "link_name": "Lookup", "type": 12, "mandatory": false }

Any help is much appreciated!

Hollie