convicts working labor camps gulag system became important component industrialization effort especially siberia ref name forcedlabor gregory paul r valery lazarev eds ''the economics forced labor soviet gulag'' stanford hoover institution press ref ref name ivanova ivanova galina ''labor camp socialism gulag soviet totalitarian system'' armonk ny e sharpe ref estimated million people passed gulag system perhaps another nbsp million experience form forced labor ref name applebaum applebaum anne ''gulag history soviet camps'' london penguin books ref
Humanities History Russian history