Are single walled boxes strong enough for books? – Packing Solution
12" x 12" x 20" Corrugated Cardboard Boxes (Brown / Kraft) - Sandbaggy
Corrugated Kraft Double Wall Shipping Boxes, 10l x 10w x 10h, 15/BD - Comp-U-Charge Inc
Amazon.com: BOX USA 25 Pack of Heavy-Duty Double Wall Corrugated Cardboard Boxes, 9" L x 9" W x 6 1/2" H, Kraft, Shipping, Packing and Moving : Industrial & Scientific