Memory Id where used list in ABAP custom prog

Dear SDN's,

There is a custom report ,here they used IMPORT v_flag FROM MEMORY ID 'V_FLG'.

So now i want to know from where they  Expoted value to MEMORY ID ' V_FLG', i want to know the program of calling

EXPORT v_flag TO MEMORY ID 'V_FLG'.

i searchrd in SDN,but i didn't get proper solution.....Please help me....anyone

Regards,

Suba