All Figures

	Figure 1: The J,H and K' magnitude of the quasars plotted as a function of redshift, with photometric uncertainties indicated by the errorbars.
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In the text

	Figure 2: The near-IR colors of the sample quasars plotted as a function of redshift. The dashed lines are the color expected from an object with a power law continuum of slope (below) and (above), while the solid lines are the colors obtained by redshifting the composite SDSS quasar spectrum (Vanden Berk et al. 2001).
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In the text

Figure 3: The spectral energy distribution of all quasars: all near-IR magnitudes have been transformed into the AB system (see text for details). The observed values have been shifted to the restframe of each object and normalized to have the same i-band magnitude. The lines indicate power laws with spectral indices from -0.25 to -1.0 (from the lower to the upper line). The object with colors much brighter than the other is 2256+0047, one of those whose continuum is not well represented by a power-law. It could be also a variable quasar.

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In the text

Figure 4: Left: the distribution of the quasars continuum power-law index from the combined fall and spring samples. The dotted line represents the distribution of spectral indices from a sample of quasars at redshift between 2 and 3.5 from Francis (1996). Right: the distribution of spectral indices derived by Ivezic et al. (2002) for about 6800 SDSS quasars with magnitude brighter than i=19. The distribution for a subsample of 440 radio-loud quasars, indicated by the triangles, is skewed towards more negative values.

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In the text

	Figure 5: The spectral index of the continuum emission: on the y axis is the value derived by Fan et al. (2001) from the low resolution spectra, on the x-axis the value derived from optical and near-IR photometry. The error bars represent the 1 uncertainties.
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In the text