Conformal Geometry of Surfaces in S4 and QuaternionsFrancis E. Burstall, Dirk Ferus, Katrin Leschke, Franz Pedit, Ulrich Pinkall · First published 2004Open the Tome
Quaternions, spinors, and surfacesPeter Norman, Franz Pedit, Ulrich Pinkall · First published 2002Open the Tome
