Referee of papers in :Journal of Mathematical Physics.,Nuclear

Physics B, Physical Review and Physical Review Letters, JHEP,

Classical and Quantum Gravity, Physics Letters B, Foundations of Physics.

Reviewer of the Mathematical Reviews.

Referee of research projects for Fondecyt(Chile), Fundación

Andes, Several Faculty of Physics in Chile, Research Corporation

(USA), ANEP(Spain).

Member of the FONDECYT Physics and Astronomy Study Group

1997-1998.