EFFECTS OF RAW MATERIAL ON METHANE PRODUCTION IN BIOGAS DIGESTER AT ROYAL UNIVERSITY OF AGRICULTURE ,ឥទ្ធិពលនៃវត្ថុធាតុទៅលើការផលិតឧស្ម័នមេតាន CH4 ក្នុងលក្ខខណ្ឌឡជីវឧស្ម័ននៅសាកលវិទ្យាល័យភូមិន្ទកសិកម្ម OUN PUTHRATY,អ៊ន់ ពុធរ៉ាទី AGE OUN 2020 B1-462 Or. phnom penh rua 2020 2020 Text x.46p. https://drive.google.com/file/d/1b_qpYurQZdUZg7kYjHBB_uaLIG4q4yq7/view?usp=sharing