from the looks of the structure of the index of notation, it was created manually, not
with any package like
glossary or an indexing tool. the arrangement of the entries is
too well defined to have endured an automatic sort.
an individual entry can be considered as being made up of three parts:
the notation example,
the definition or explanation,
and the references.
the references can be identified in the text by the use of
\label, and then cited
in the list of notation using
\ref. (more than one label will be needed if more
than one reference is wanted.)
the left-hand column, with the notation examples, should be of fixed width. if none
of the examples requires more than one line, then it can be set in a box of fixed width
and the right-hand column, with definitions, can be set as ordinary text (preferably
ragged right) with a left indent the width of the box containing the example.
i will post code for this structure after i've worked out the case where the left
column requires more than one line.