I previously purchased and used: Visual Basic 6.0 Reference Book Vol. 1 Visual Basic 6.0 Reference Book Vol. 2 Published by Natsume-sha. Vol. 1: ¥2,500 + tax Vol. 2: ¥2,400 + tax Size: Vol. 1: 13cm x 18.5cm x 4cm Vol. 2: 13cm x 18.5cm x 3.5cm Individual sales and bundled sales are both possible. Please feel free to contact me. There are no markings inside the books. They are in good condition. Please refer to the photos for consideration.