Member 4 of Quantou Formation -Yaojia Formation

Qingshankou Formation-Yaojia Formation

the 2nd Member of Shanxi Formation—the 8th Member of lower Shihezi Formation

backing burr

ball-shaped burr

bur [= burr]

Burr

burr breast

Burr Distribution

burr drill

burr free perforation

burr grinder

burr height

Burr hole and drainage

burr holes of kull

burr lathe

burr masher

burr mill

burr minimization