lispdoc - results for reduce

(reduce function sequence &rest args &key (key nil) from-end (start 0)
 (end nil) (initial-value nil ivp))
(defun merge-tree-list (trees)
  "takes a list as input and reduces the list to a simple
object through calls to MERGE-TREES."
  (reduce #'merge-trees trees))
Mentioned in:
CLtL2 - 14.2. Concatenating, Mapping, and Reducing Sequences
CLtL2 - 20.1. Run-Time Evaluation of Forms
HyperSpec - Function REDUCE
On Lisp - Common Lisp Evolves
PCL - combining probabilities
PCL - sequence mapping functions
Successful Lisp - chapter12