A nonvolatile semiconductor memory having a common source line driving circuit which simply ensures a sufficient threshold voltage margin for erased memory cells during an erase verifying operation. The nonvolatile semiconductor memory includes a resistance which cause, during an erase verifying...http://www.google.com/patents/US5808935?utm_source=gb-gplus-sharePatent US5808935 - Common source line driving circuit for use in nonvolatile semiconductor memories 
