1. Pulmonary, Critical Care & Sleep Medicine, Texas A&M University, Corpus Christi, 1177 West Wheeler Avenue, Suite 1, Aransas Pass, TX 78336, USA
2. Corpus Christi Medical Center, 7101 South Padre Island Drive, Corpus Christi, TX 78412, USA
3. Universidad Autonoma de Baja California, Avenue Álvaro Obregón Sn, Nueva, 21100 Mexicali, BC, Mexico
4. Dorrington Medical Associates, 2219 Dorrington Street, Houston, TX 77030, USA
5. Pulmonary Associates, 1177 West Wheeler Avenue, Aransas Pass, TX 78336, USA
6. Texas A&M University Health Science Center, 8447 State Highway 47, Bryan, TX 77807, USA
7. The University of Texas Health Science Center, 7000 Fannin Street, Houston, TX 77030, USA
8. University General Hospital, 7501 Fannin Street, Houston, TX 77054, USA