Amazon Japan listing
Vol.4 (eps 11 to 14) - 8190yen, 2/22
via CD Japan
Includes episodes 11 through 14 with a special booklet and jacket illustrated by Nobuteru Yuki.
Special Features: talk between Izubuchi Yutaka and Yoshikazu Yoshihiko, creditless opening, digest of chapter 2, PR footage, audio commentary
First Press Detail: special sleeve newly illustrated by Naoyuki Kato