@book{4821,
	author = {Singh, Bhawani. and Goel, R. K.,},
	title = {Tunnelling in weak rocks /},
	publisher = {Elsevier,},
	year = {c2006.},
	address = {Amsterdam ;},
	edition = {1st ed.},
	url = {http://www.loc.gov/catdir/enhancements/fy0665/2006297064-d.html}
}