The names of the "Paper Sisters" are loosely inspired by three famous Hong Kong actresses: Maggie Cheung, Michelle Yeoh and the late Anita Mui.
Woo-san, the pigeon in the series, is named after Hong Kong action director John Woo. John Woo usually has a shot with a pigeon flying in his movies.
Akage no Anne (Red-Haired Anne), the book that Hisami reads, is the Japanese adaptation of L.M. Montgomery's classic novel Anne of Green Gables.
The final remark made by Yomiko, in episode 26, about paper being in the heavens, is a pun in Japanese. The word for paper, "kami", can also (written using a different kanji) mean "god(s)". Taken in context, it becomes an indirect reference to a quotation from Robert Browning, "God is in His Heaven, all's right with the world" - a fitting way to mark a happy ending.
R.O.D actually stands for 'Read Or Dream', not 'Read Or Die'.