From single solitons to auto-Bäcklund transformations and hereditary symmetries
In: Topics in Soliton Theory and exactly solvable nonlinear Equations, Vol. 1987, page 230-254
Function algebras and a theorem of Mergelyan for vector-valued functions
In: Papers from the Summer Gathering on Function Algebras, University of Aarhus (Denmark), Various Publications Series No. 9, Vol. 1969, page 1-10