Found in the back of Tsubasa: Reservoir Chronicle Volume 1. Published in May 2004.

"About the Creators

CLAMP is a group of four women who have become the most popular manga artists in America— Satsuki Igarashi, Mick Nekoi, Mokona Apapa, and Nanase Ohkawa. They started off as doujnishi (fan comics) creators, but their skill and craft brought them to the attention of publishers very quickly. Their first work from a major publisher was RG Veda, but their first mass success was with Magic Night Rayearth. From there, they went on to write many series, including Cardcaptor Sakura and Chobits, two of the most popular manga in the United States. Like many Japanese manga artists, they prefer to avoid the spotlight, and little is known about them personally."

Name: Satsuki Igarashi
Birthday: February 8
Blood Type: A
Hometown: Shiga
Role: Designer, Art Assistant
 

Name: Nanase Ohkawa
AKA: Ageha Ohkawa
Birthday: May 2
Blood Type: A
Hometown: Osaka
Role: Team Leader, Story & Script

Name: Tsubaki Nekoi
AKA: Mick Nekoi
Birthday: January 21
Blood Type: O
Hometown: Kyoto
Role: Art Assistant, Chibi Artist

Name: Mokona
AKA: Mokona Apapa
Birthday: June 16
Blood Type: A
Hometown: Kyoto
Role: Lead Artist, Colors

Angelic Layer (1999-2001)
Cardcaptor Sakura (1996-2000)
Cardcaptor Sakura: Clear Card Arc (2016-Present)
Chobits (2000-2002)
CLAMP School Detectives (1992-1993)
Clover (1997-1999)
Drug & Drop (2011-)
Duklyon: Clamp School Defenders (1991-1993)
Gate 7 (2010-)
High & Low G-Sword (2017-2017)
Kobato (2004-2011)
Legal Drug (2000-2003)
Magic Knight Rayearth (1993-1996)
Man of Many Faces (1989-1991)
Miyuki-chan in Wonderland (1993-1995)
RG Veda (1989-1996)
Snow Goddess Tales (1992-1992)
Suki Dakara Suki (1999-2000)
The Legend of Chun Hyang (1992-1994)
The One I Love (1993-1995)
Tokyo Babylon (1990-1993)
Tsubasa Reservoir Chronicle (2003-2009)
Tsubasa World Chronicle: Nirai Kanai-hen (2014-2016)
Wish (1995-1998)
X (1992-)
xxxHolic (2003-2011)
xxxHolic Return (2013-)

OTHER WORKS
All About CLAMP (2009-)
CLAMP Gengashu Memories (2018-)
CLAMP Pia (2012-)