APA
Ministry of Environment and Natural Resources, . (1997). Environmental Guidelines for Road and Rail Development in Sri Lanka. Colombo: Ministry of Environment and Natural Resources.
Chicago
Ministry of Environment and Natural Resources, . 1997. Environmental Guidelines for Road and Rail Development in Sri Lanka. Colombo: Ministry of Environment and Natural Resources.
Harvard
Ministry of Environment and Natural Resources, . (1997). Environmental Guidelines for Road and Rail Development in Sri Lanka. Colombo: Ministry of Environment and Natural Resources.
MLA
Ministry of Environment and Natural Resources, . Environmental Guidelines for Road and Rail Development in Sri Lanka. Colombo: Ministry of Environment and Natural Resources. 1997.