Quotes in Latex

In print, opening and closing double quotes are different;  in TeX  left
are coded as `` (on my keyboard this is on the left-most key on the
upper row below ~).  Right quotes are given by the two symbols '' (which
is on the key below the single symbol " which is NOT used).  Thus we
have ``quote, unquote''.  The same goes for single quotes, or `quote,
unquote'.  One use of single quotes is when nested inside double quotes,
and it some times happens that a single quote directly follows or is
proceeded by double quotes;  coding
this as ``` or '''  is incorrect.  You need to introduce a space between
the single and double quotes and this requires the use of the thinspace
\, (=\thinspace). Using this gives `/,`` and '/,'' and the spacing is