Shuhei Takeyama, Hironari Hanaoka, Akiyoshi Hashimoto, Yusho Ishii, Yuka Shimizu, Toshiharu Takeuchi, Shuhei Shimoyama, Masataka Kuwana, Tomoaki Higuchi, Masaru Yoshimura, Hiroshi Kataoka, Yuko Shirota, Kazufumi Okada, Yoichi M. Ito, Ryo Hisada, Kazuro Kamada, Sho Ishigaki, Tetsuya Horita, Tatsuya Atsumi, Masaru Kato; the HAPPINESS study group A cohort study in HigAshi-nippon of Pulmonary hyPertensIoN in systEmic SclerosiS (HAPPINESS study): protocol and baseline data for an observational study BMC Rheumatol, in press IF 2.1