The Index for a month shall be the arithmetic average of the high and low 
prices per Short Ton for such calendar month 
of 26 Lb. Semichemical Medium, stated in U.S. Dollars, delivered in the 
Eastern U.S., published under the headings:  
"Price Watch: Paperboard/Packaging: Grade: Corrugating medium (26-lb): 
Semichemical, East" in the issue of Pulp & 
Paper Week that reports prices effective for such calendar month.