  Symmetric Space Sine-Gordon theories are two-dimensional massive integrable
field theories, generalising the Sine-Gordon and Complex Sine-Gordon theories.
To study their integrability properties on the real line, it is necessary to
introduce a subtracted monodromy matrix. Moreover, since the theories are not
ultralocal, a regularisation is required to compute the Poisson algebra for the
subtracted monodromy. In this article, we regularise and compute this Poisson
algebra for certain configurations, and show that it can both satisfy the
Jacobi identity and imply the existence of an infinite number of conserved
quantities in involution.
