To reference the types, items and subprograms that are declared within a package specification, you must use the dot notation. For example: 

package_name.type_name
package_name.item_name
package_name.subprogram_name

You can execute the following SQL statement to invoke a function from the emp_admin package specification. 

SELECT emp_admin.get_dept_name(10) FROM DUAL;

This statement invokes the get_dept_name function that is declared within the package emp_admin, and passes the department number as an argument to the function. The function returns the name of the department. The returned value is ACCOUNTING, which corresponds to department number 10.