The control text shows either what should appear on the screen, what variable should be accessed in the model or, for tool controls, what name the tool output should be given for printing. The control text must appear surrounded by double quotes ", and can contain anything except double quotes. To include a double quote within the control text precede the double quote by a backward slash \" as in
BUTTON,"Start \"targeting\"",50,90,0,0,C,Ss,MENU>RUN
If you are working with the Control Definition dialog you do not need to worry about quotes - Vensim will automatically put those in place. Just type in the exact string you want to use or have appear.