I recently acquired a porcelin Standard Oil of La sign - 20 x 22 inches - with a flange - very good shape - 5 colors - has green border with black trim- with white inside - lettering is Red and Black - says " Stanocola Polarine The "Standard" Motor Oil" - small emblem in bottom right side of sign - a circle in red with orange background - says around the circle " Standfard Oil Company of Louisiana with 2 stars - in the middle - where it is orange is an emblem that says Stancola Polarine and another emblem - Need to know the history of this, or where to look for info on it - also would like to know the approximate value and age. Any info appreciated. Thanks, The Traveler