Judge Arthur L. Alarcón and Professor Paula M. Mitchell have written an update to their groundbreaking 2011 study about the true costs of California's Death Penalty:
Costs of Capital Punishment in California: Will Voters Choose Reform this November?.

Their original study, Executing the Will of the Voters: A Roadmap to Mend or End the California Legislature’s Multi-Billion-Dollar Death Penalty Debacle, was published as part of a special issue:
Rethinking the Death Penalty in California.