Mighty Yukiko and Toshimi Minami illustlation book "Moon & Southern cross" are sold out. But you can find it any auction site.
Maybe alot of people don't know how to seach the adult category books. First, look at the top page of Y!auction. You can find category list on the upper left of this. Lets select "その他" (lowest one), next "アダルト" (second category from low, means "adult" ) .
when you get on top page of Y!auction'S adult category, then input some words "レッスル", "レッスルエンジェルス".