Complex sentence: The chapters of the manga series "Marmalade Boy" were written by Wataru Yoshizumi; the first premiered in the May 1992 issue of "Ribon" where it was serialized monthly until its conclusion in the October 1995 issue.
Split into simpler sentences: The chapters of the manga series "Marmalade Boy" were written by Wataru Yoshizumi. The first chapter premiered in the May 1992 issue of "Ribon" where it was serialized monthly until its conclusion in the October 1995 issue.