That's not the case (1-9 volumes of volume)

Publisher: Shogakukan
Author: Izumi Kaneyoshi
Size: 112mm x 174mm
Number of books: 9
Language: Japanese
Category: Girl manga, manga
Latest issue date: 2006-07-26

Synopsis:
The strongest beautiful twins in history, Tetsu & Retsu. Fortunately (?) Sister Shizu, who is beloved by them, has been a very hardcore syscon that feels only in the quiet, although Tetsu and Retsu are very motivated for 16 years. Three people send an adolescent life of weak meat -and -strong food under one roof, but is the "Shizuka and Foster the Theory" emerged?