A solution for the "Ibid." problem proposed by Gene Kim here: https://twitter.com/RealGeneKim/status/1201922587346866176?ref_src=twsrc%5Etfw. We avoid explicit recursion

ibid.clj

(defn replace-ibids [coll]
  (letfn [(go [{:keys [acc latest]} e]
             (if (and (= e "Ibid.")
                      (some? latest))
               {:acc (conj acc latest) :latest latest}
               {:acc (conj acc e) :latest e}))]
    (if (= "Ibid." (first coll))
      (ex-info "Invalid ibid" {})
      (-> (reduce go {:acc []} coll)
         :acc))))


(def authors ["toto" "Ibid." "tato" "Ibid." "Ibid." "tito" "Ibid."])
(replace-ibids authors)
;; => ["toto" "toto" "tato" "tato" "tato" "tito" "tito"]
(replace-ibids [])
;; => []
(replace-ibids ["toto"])
;; => ["toto"]
(replace-ibids ["Ibid."])
;; => #error {
;; :cause "Invalid ibid"
;; :data {}
;; ...