erc:
who: Hersey, Mayo D.
what: Aeronautic instruments. Section 1: general classification of instruments and problems including bibliography
when: 1925
where: https://digital.library.unt.edu/ark:/67531/metadc65775/
erc-support:
who: University of North Texas Libraries
what: Permanent: Stable Content:
when: 20081203
where: https://digital.library.unt.edu/ark:/67531/