Quick answer — Shungiku Nakamura worked on Sekai Ichi Hatsukoi - The World's Greatest First Love: The Case of Takafumi Yokozawa (Original Character Design), Sekaiichi Hatsukoi OVA (Original Creator), Sekaiichi Hatsukoi: Valentine-hen (Original Creator) and 8 more anime.
Shungiku Nakamura worked on Sekai Ichi Hatsukoi - The World's Greatest First Love: The Case of Takafumi Yokozawa (Original Character Design), Sekaiichi Hatsukoi OVA (Original Creator), Sekaiichi Hatsukoi: Valentine-hen (Original Creator), Sekai Ichi Hatsukoi - The World's Greatest First Love Season 2 (Original Creator), Junjou Romantica 3 (Original Creator), Junjou Romantica (OVA) (Script), Sekaiichi Hatsukoi: Propose-hen (Original Creator), Hybrid Child (Original Creator) and 3 more.