i don't have any experience with this stuff, i have a friend who is a horticulturist.
boy did i get an education about it. digging it out, well i am sure you read up on it, and you can't pull them.
roundup apparently does not get the job done. look up 'speed zone lawn and weed killer'. it is a herbicide, but apparently it takes care of this stuff with one application and does not affect lawn.