Write SQL query to solve given problem: Please give the additional contact information of the oldest employee with the jod position of sales person.. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T2.AdditionalContactInfo FROM Employee AS T1 INNER JOIN Person AS T2 ON T1.BusinessEntityID = T2.BusinessEntityID WHERE PersonType = 'SP' ORDER BY T1.BirthDate ASC LIMIT 1