1. Begehr H., Complex analytic methods for PDE. World scientific, Singapore, London, 1994.
2. Bojarski B., Old and new on Beltrami equations. Functional analytic methods in complex analysis and applications to PDE. World scientific. Trieste 1990.
3. Brackx F.,Delanghe R., Sommen F., Clifford Analysis, Pitman, London, 1982.
4. Gilbert R., Buchanan J.,First order systems a function theoretic approach. Academic Press, New York. 1983.
5. Goldschmidt B., Properties of generalized analytic vectors in R
n. Math. Nachr. 103, 1981, 245–254.