... discs

Figures 7-17 and Tables 4-7 are only available in electronic form at http://www.aanda.org

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...1,3,

Visiting Astronomer of CASLEO, operated under agreement among CONICET and the National Universities of La Plata, San Juan and Córdoba, Argentina.

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... IRAF

IRAF is distributed by the National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the National Science Foundation.

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