tax
   CASE pschoice  = 'T'
     STORE F TO psmain
   CASE pschoice = 'C'
     *
   CASE pschoice = 'E'
     STORE F TO psmain
     STORE F TO psmore
     CANCEL
ENDCASE

@ pscount,11 GET psisbn
READ
SELECT SECONDARY
USE INVENT
GOTO TOP
LOCATE FOR isbn = psisbn
SET CONSOLE OFF
IF EOF
   SET CONSOLE ON
   @ 21,10 SAY '*** ISBN NOT IN INVENTORY ***'
   SET CONSOLE OFF
   WAIT
   SET CONSOLE ON
   @ 21,10 SAY '                                 '
   LOOP
ENDIF
SET CONSOLE ON
STORE