Trigonometric Lax matrix for the Kowalevski gyrostat on so(4)
  We present trigonometric Lax matrix and classical $r$-matrix for the Kowalevski gyrostat on $so(4)$ algebra by using auxiliary matrix algebras $so(3,2)$ or $sp(4)$. 
I.V. Komarov, A.V. Tsiganov