Where are PP Ups in Pokemon Red Blue and Yellow?

To my knowledge, there are exactly 5 PP Ups in Pokemon R/B/Y.

1. Second floor of the Unknown Dungeon

2. Hidden in an alcove in a room up and to the right of where you found Zapdos.

3. Hidden halfway down the right side of Cycling Road.

4. Hidden to the right of the sign on Route 13.

5. Hidden in a row of trees to the right of the Game Corner in Celadon City.