Pink Pig Square 4 x 4 Inch Sketchbook: 35 Pages, 150 gsm – Perfect Paper Company
Seawhite Board Cover Square Sketchbook 30cm x 30cm | Hobbycraft
Square Format Sketchbooks | Stillman and Birn
Moleskine 19 x 19 cm Square Size Art Collection Sketch Album, Sketchbook , Paper Suitable for Pens, Pencils, Charcoal, Colour Black, 88 Pages : Moleskine: Amazon.co.uk: Stationery & Office Supplies