One method of binding is “elasticized bands”. As indicated here the sheets can be added or subtracted as the elastics are removed. It is not environmentally friendly. The elastics can be imprinted as indicated. They come in patterned colours, solid colours and different widths. The book can be of any size or thickness. The book is bound as shown, the back cover is full surface glued on the inside cover. The advantage of using an elasticized band is that you can take sheets in and out by simply stretching the elastic.