Gift Wrapping - Creative Ideas from Japan
by KUNIKO EKIGUCHI
Paperback 124 Pages
ISBN-10: 0870117688 ISBN-13: 9780870117688
Publisher: Kodansha International
Pub date: Sep 15, 1987
Preview available on Google Books
This was the book that inspired me to try my hand at Tsutsumi, both by following its examples, and by improvising freely.
Extremely recommended: it's probably out of print now, but you can easily find copies around the internet.