APA

Lorentzen R. J., Fjelde K. K., Froyen J., Lage A. C., Petrobras, SPE Annual Technical Conference and Exhibition (2001 sept. 30-3 oct. : New Orleans), Fjelde K. K., Froyen J., Lage A. C. & Petrobras.Underbalanced and low-head drilling operations. : .

Chicago

Lorentzen Rolf J, Fjelde Kjell Kare, Froyen Jonny, Lage Antonio C.V.M, Petrobras, SPE Annual Technical Conference and Exhibition (2001 sept. 30-3 oct. : New Orleans), Fjelde Kjell Kare, Froyen Jonny, Lage Antonio C.V.M and Petrobras.Underbalanced and low-head drilling operations. : .

Harvard

Lorentzen R. J., Fjelde K. K., Froyen J., Lage A. C., Petrobras, SPE Annual Technical Conference and Exhibition (2001 sept. 30-3 oct. : New Orleans), Fjelde K. K., Froyen J., Lage A. C. and Petrobras.Underbalanced and low-head drilling operations. : .

MLA

Lorentzen Rolf J, Fjelde Kjell Kare, Froyen Jonny, Lage Antonio C.V.M, Petrobras, SPE Annual Technical Conference and Exhibition (2001 sept. 30-3 oct. : New Orleans), Fjelde Kjell Kare, Froyen Jonny, Lage Antonio C.V.M and Petrobras.: . .