In the appendix, examples use incorrect invocations of fn:fold-left - the order of arguments is ($f, $zero, $seq) - whereas it should be ($seq, $zero, $f). 

This concerns the following examples (XSLT and XQuery):
* eg:distinct-nodes-stable
* eg:higheest
* eg:lowest


Example:

declare function eg:highest(
                     $f as function(item()) as xs:anyAtomicType, 
                     $seq as item()*)
                  as item()* {
     fn:fold-left(
       function($highestSoFar as item()*, $this as item()*) as item()* {
         let $thisValue := $f($this)
         let $highestValue := $f($highestSoFar[1])
         return
           if ($thisValue gt $highestValue)
             then $this
           else if ($thisValue eq $highestValue)
             then ($highestSoFar, $this)
           else $highestSoFar
       }, fn:head($seq), fn:tail($seq))
};