000 00268pam a2200097a 44500
082 _aTR
_bRI-9227
100 _aJohn E. Pahlman
245 1 _aZero-surface-charge-controlled drilling for enhanced penetration and extended bit life
260 _a
_b
_c
997 _aTR6601 C
999 _c405767
_d405767