Oracle Database Discussions

Hi,
how to determine the valide lower and higher limits snapshot to avoid the follwing error :

SQL> SELECT * FROM aL_emp
2 VERSIONS BETWEEN TIMESTAMP
3 SYSTIMESTAMP - INTERVAL '100' MINUTE AND
4 SYSTIMESTAMP - INTERVAL '1' MINUTE;
SELECT * FROM aL_emp
*
ERROR at line 1:
ORA-30052: invalid lower limit snapshot expression
And how to find the largest interval ?

Many thanks.