... scales

Based in part on observations collected at the European Southern Observatory (ESO, La Silla).

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...ékers^1,2,

Also, Chercheur Qualifié au Fonds National de la Recherche Scientifique (FNRS, Belgium).

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... quasars

All throughout this paper we use "quasar'' without any distinction between quasars and quasi-stellar objects (QSOs).

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... conditions

The fact that this modified sample contains 29 objects exactly as the original one is only chance. Several objects are indeed different.

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