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		<text> 0</text>
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	<g transform="translate(59,286)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 5</text>
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	<g transform="translate(59,232)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 10</text>
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		<text> 15</text>
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		<text> 20</text>
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		<text> 25</text>
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	<g transform="translate(59,13)" style="stroke:none; fill:black; font-family:sans-serif; font-size:12.00; text-anchor:end">
		<text> 30</text>
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		<text> 1986</text>
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		<text> 1992</text>
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		<text> 1998</text>
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		<text> 2004</text>
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		<text>Number of references</text>
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		<text>Year of publication</text>
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