National Environment Commission. Highways and roads : Bhutanese environmental assessment sectoral guidelines / - Thimphu, Bhutan : National Environment Commission, February 1999. - iii, 3-2 p. : ill. ; 28 cm. ISBN: NA LC Class. No.: GD00466-GD00467 Dewey Class. No.: A5.5 / NEC Gov. Doc. Class. No.: A5.5