Mikhail Troitskiy exlpores the sources of mutual reassurance in Sino-Russian relations. In his view, the surprising lack of openly balancing behavior by Moscow and Beijing vis-a-vis each other is best explained by their mutual perceptions of their respective policymaking processes and by some costly signals of shared commitment to counterbalancing the United States.
See the report at Clingendael (PDF) (Netherlands Institute of International Relations) or at academia.edu