What forms of checks are undertaken to verify signatures?

Law on Referendum (1995, last amended in 2008)

http://aceproject.org/ero-en/regions/asia/KZ/kazakhstan-constitutional-law-on-referenum-1995/view

Article 14. The order and timing for collection of signatures

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7. Within three days after completion of collection ofsignatures the filled subscription list shall be handed over by personsinvolved in the collection of signatures to the territorial electioncommission, which within ten days shall examine the authenticity of citizens’signatures at the subscription lists with the assistance of employees ofpassport services, draw up a corresponding protocol and submit it to the CentralElection Commission.