"Resources" is truly not a field on Project. If you need to fetch the project's resources, query "RegularResourceLink" filtering by the WorkItem field. You can reach the resources information with the Resource field.
Use the Clarizen page 'Settings -> configure' to figure out available fields for each entity and their API name. You can also get programmatically with the _DescribeEntitiesMessage. _Also check the manual page:
Hope this helps,