Long-Term Safety and Efficacy of Morphine Sulfate and Naltrexone Hydrochloride Extended Release Capsules, a Novel Formulation Containing Morphine and Sequestered Naltrexone, in Patients with Chronic, Moderate to Severe PainLynn R. Webster, Joseph Stauffer, Chao Wang et al.|Journal of Pain and Symptom Management|2010Cited by 40