<?xml version="1.0" encoding="UTF-8"?>
<xml><bibliography><APA>Boonerb Khettsakorn. (1989) Pulmonary function in smokers. Mahidol University,:ม.ป.ท.</APA><Chicago>Boonerb Khettsakorn. 1989. Pulmonary function in smokers. ม.ป.ท.:Mahidol University,;</Chicago><MLA>Boonerb Khettsakorn.  Pulmonary function in smokers.  ม.ป.ท.:Mahidol University, 1989. Print.</MLA></bibliography></xml>
