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Cross References
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One reason for numbering things like figures and equations 
is to refer the reader to them, as in "See Figure 3 for more 
details." 

\label: Assign a symbolic name to a piece of text. 
\pageref: Refer to a page number. 
\ref: Refer to a section, figure or similar. 

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	\label ::label::
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\label{key} 
A \label command appearing in ordinary text assigns to the 
key the number of the current sectional unit; one appearing 
inside a numbered environment assigns that number to the key. 

A key can consist of any sequence of letters, digits, or 
punctuation characters. 

Upper and lowercase letters are different. 

To avoid accidentally creating two labels with the same name, 
it is common to use labels consisting of a prefix and a suffix 
separated by a colon. The prefixes conventionally used are 
	cha for chapters 
	sec for lower-level sectioning commands 
	fig for figures 
	tab for tables 
	eq for equations 
Thus, a label for a figure would look like fig:bandersnatch. 
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	\pageref ::pageref::
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\pageref{key} 
The \pageref command produces the page number of the place 
in the text where the corresponding \label command appears. 
ie. where \label{key} appears. 
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	\ref ::ref::
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\ref{key} 
The \ref command produces the number of the sectional unit, 
equation number, ... of the corresponding \label command.