Mike Singletary is best known for playing with which NFL team?

What position did Dick Butkus primarily play? Which college was Dick Butkus playing for when he entered the NFL? What jersey number did Dick Butkus wear with the Bears? What position did Mike Singletary primarily play? Which college was Mike Singletary playing for when he entered the NFL? What jersey number did Mike Singletary wear with the Bears? What position did Jack Lambert primarily play? Jack Lambert is best known for playing with which NFL team?