#import Foundation in subclasses

#import <Foundation/Foundation.h> is present in main.m and every header file belonging to a subclass of NSObject, but seems to be left out in the BNREmployee.h (p. 142), the subclass to BNRPerson. Are there any “standards” regarding imports and class structure?

I had a similar question. What is the standard for imports that already include foundation library.

Good question. I overlooked that. Anybody figure this out?