“Preface / Préface / Előszó” and “Notes / Notes / Jegyzetek”, in Béla Bartók: Mikrokosmos. 153 Progressive Piano Pieces in Six Volumes. London–New York, ©1940, Boosey & Hawkes H. 15196, 15197, 15192, 15191, 15189, 15187, [5–7], [2–4], [4–6], [3–5], [31–32], [52], [38–39], [44].
Collected edition: Essays, 424–425; BBI/1, 83–85.
Source: BBA