The student is quoting from page 26 of the following source:

Hawley, Richard A. Thinking about Drugs and Society: Responding to an Epidemic. New York: Walker, 1988. Print.

“The use of cannabis has been traced back four thousand years to ancient China,” writes Richard A. Hawley (26).

“The use of cannabis has been traced back four thousand years to ancient China,” writes Richard A. Hawley (p. 26).

The abbreviation “p.” is not used with page numbers in MLA citations.