don't know if you mean this Michael...I do not profess to much knowledge of above...Gerard Greenfield had a piece in *Against The Current* last year in which he distinguished between documented and undocumented migrant workers in China...latter are paid less and are under constant threat of being turned over to authorities by employers...'legal' migrant workers are required to submit ID cards, residency documents, and provincial entry permits to emmployers which prevents them from being able to leave on their own accord...strict control over internal migration was further institutionalized in 1996 when migrant workers were required to register at family planning centers...proof of sterilization is required for migrant women applying for work in Fujian Province... Michael Hoover