Riverside County and San Bernardino County to the north form this metro area. Like many such metro areas in the Southwest, it extends far into uninhabited desert areas, in this case east through the Mojave Desert to the Nevada/Arizona border. Larger than nine U.S. states, it is often referred to as the Inland Empire.
I agree with tchrist that the word doctor in doctor appointment is a noun (attributive noun I believe), although the definition of an attributive noun is a noun used as an adjective, so maybe it's just semantics at some point.
An appointment letter is a necessary part of the entire job process. The appointment letter should look professional and provide important details to the new employee. The appointment letter is also considered official notice that the individual has been hired. Therefore, the letter also serves as a very valuable record and contract between the employer and the employee. Proper format is important. The 8 different appointment letter samples here are representative of proper Appointment Letter Format. They are easy to customize to your specific requirements.