00665cam a2200217 a 4500 3700204 BD-DhUL 20170418142411.0 850514s1980 nyua b i000 0 eng d VIT eng BD-DhUL BD-DhUL BD-DhUL d------ 665.7 19 UNG United Nations Guidebook on biogas development : United Nations no. 21 / New York : United Nations, 1980. xi, 127 p. : ill., graphs ; 29 cm. Energy resources development series ; no. 21 Biogas Developing countries. United Nations. ddc REF 184939 184939