The impact of sleeping in an elevated upper body position during acclimatization to high altitude on acute mountain sickness and pulmonary artery systolic pressure oleh Maren Graß, Christian Apel, Daniela Bertsch, Carina Cerfontaine, Michael van der Giet, Simone van der Giet, Miriam Haunolder, Nina Hundt, Julia Jäger, Christian Kühn, Sonja Museol, Lisa Timmermann, Knut Wernitz, Ulf Gieseler, Audry Morrison, Volker Schöffl, Thomas Küpper