APA (7th ed.) Citation

Laupland, K. B., Helmersen, D., Zygun, D. A., & Viner, S. M. Sildenafil Treatment of Primary Pulmonary Hypertension. Wiley.

Chicago Style (17th ed.) Citation

Laupland, Kevin B., Doug Helmersen, David A. Zygun, and Sidney M. Viner. Sildenafil Treatment of Primary Pulmonary Hypertension. Wiley.

MLA (9th ed.) Citation

Laupland, Kevin B., et al. Sildenafil Treatment of Primary Pulmonary Hypertension. Wiley.