Unknown Oil Painting by G. Whitman

This is a beautiful fall colored landscape picture of a river, mountains and trees. This is a large painting on canvas that measures 24 x 20 for the canvas alone, and with the solid wood frame that it is in it measures 32 x 28 Painting needs to be cleaned as it was picked up out of an estate clean up, however the is one pencil led spot that appears as though it may go through and through but is in the sky area and not very noticable to the average person. There are some crackling of the thicker paint in a couple of places but the majority of the painting is good. Painting is signed G. WhiTman and has an Artistic Interiors label authenticating it as an origional oil painting with a certificate number of 195704. Frame on the back states "HECHO EN MEXICO" on the flap that is present attaching to the back of the canvas frame is the name Fraiser, the address 108 Green and with the additional writing which appears to state Houre/Centa and has a date 12/  /1981. I cannot read the actual day. This painting appears to have been painted with the canvas flas and was mounted to it's frame after the painting was done. I have multiple pics, however they are all larger than your sight allows