Criteria for bioreactor comparison and operation standardisation during process development for mammalian cell culture by Platas Barradas Oscar, Jandt Uwe, Da Minh Phan Linh, Villanueva Mario, Rath Alexander, Reichl Udo, Schräder Eva, Scholz Sebastian, Noll Thomas, Sandig Volker, Pörtner Ralf, Zeng An-Ping