V O L . 7 , D O C . 3 9 a P R O P A G A T I O N O F S O U N D 3 7 PD (NL-LeU, Collectie Bibliotheca Publica Latina 3545, Albert Einstein Manuscripts). [123 454]. [1]The last two pages of corrected page proofs of Einstein 1920c (Vol. 7, Doc. 39). Einstein replaced the crossed-out text with a corrected version, included in Einstein 1920c (Vol. 7, Doc. 39), and extant in manuscript as [123 455]. See also Velsen 2005 for an analysis of Einstein’s corrections. [2]The paper was published on 29 April 1920. [3]The corrected equation (18) appears in the published version of Einstein 1920c (Vol. 7, Doc. 39).