@book{150194,
	title = {Critical sour drilling},
	publisher = {Petroleum Industry Training Service (PITS)},
	year = {2002},
	address = {Calgary, Alberta},
	note = {Sitio web visitado en julio de 2003 ; El texto completo del documento está disponible en PDF},
	url = {http://www.psc.ca/manuals/pdffiles/irpvol_1.pdf}
}