The Free On-line Dictionary of Computing (30 December 2018):

Plankalkül

    (Or "Plankalkuel" if you don't have
   umlauts).  The first programming language, designed by Konrad
   Zuse, ca. 1945.  Zuse wrote "Rechenplan allgemeiner Struktur"
   in 1944 which developed into Plankalkül.  Plankalkül included
   arrays and records and used a style of assignment in
   which the new value appears on the right.

   Zuse wrote Plankalkül for his Z3 computer (finished before
   1945) and implemented it on there as well.  Much of his work
   may have been either lost or confiscated in the aftermath of
   World War II.

   ESR Plankalkül
   (http://tuxedo.org/~esr/retro/plankalkuel/).

   ["The Plankalkül of Konrad Zuse", F.L. Bauer et al, CACM
   15(7):678-685, Jul 1972].

   (2002-05-28)