erc: who: Tate, D.D. what: Computer systems and software description for Standard-E+ Hydrogen Monitoring System (SHMS-E+) when: 19970501 where: https://digital.library.unt.edu/ark:/67531/metadc680501/ erc-support: who: University of North Texas Libraries what: Permanent: Stable Content: when: 20081203 where: https://digital.library.unt.edu/ark:/67531/