SICP in Clojure: Chapter 1, Exercise 29

This is my Clojure solution to Chapter 1, Exercise 29:

(ns sicp.ch1.ex29
  (:require [sicp.ch1.ex15 :as ch1-ex15]))

(defn sum
  [term a succ b]
  (if (> a b)
    0
    (+ (term a)
       (sum term (succ a) succ b))))

(defn integral
  [f a b dx]
  (* (sum f (+ a (/ dx 2.0)) (partial + dx) b)
     dx))

(defn integral-simpson
  [f a b n]
  (let [h (/ (- b a) n)]
    (* (sum #(let [m (cond
                       (zero? %) 1
                       (= n %)   1
                       (even? %) 2
                       (odd? %)  4)]
               (* m (f (+ a (* % h)))))
            0
            inc
            n)
       (/ h 3))))

(integral ch1-ex15/cube 0 1 0.01) ; => 0.24998750000000042

(integral ch1-ex15/cube 0 1 0.001) ; => 0.249999875000001

(double (integral-simpson ch1-ex15/cube 0 1 100)) ; => 0.25

(double (integral-simpson ch1-ex15/cube 0 1 1000)) ; => 0.25