NCT00412022. HOBOE: A Phase 3 Study of Adjuvant Triptorelin and Tamoxifen, Letrozole, or Letrozole and Zoledronic Acid in Premenopausal Patients With Breast Cancer. (HOBOE) - clinicaltrials.gov; https://clinicaltrials.gov/ct2/show/NCT00412022 (NIH US National Library of Medicine, 2006)