On the number of square classes of a field of finite level. Becher, Karim Johannes — 2001 Documenta Mathematica
Symbol lengths in Milnor K -theory. Becher, Karim Johannes; Hoffmann, Detlev W. — 2004 Homology, Homotopy and Applications
Isotropy of quadratic spaces in finite and infinite dimension. Becher, Karim Johannes; Hoffmann, Detlev W. — 2007 Documenta Mathematica