@Article{wirth-sieb,
year={2021},
author={Wirth, Claus-Peter},
title={Gisbert Hasenjaeger and a Most Interesting Unpublished Draft for Hilbert and Bernays' ``Grundlagen der Mathematik''},
journal={Siegener Beitr\"age zur Geschichte und Philosophie der Mathematik, ISSN 2197-5590},
volume={14},
pages={1--56},
note={Thoroughly rev.\ and improved version of \cite{swp-2017-01}. \url{https://www.universi.uni-siegen.de/katalog/reihen/sieb}},
}

@Book{swp-2017-01,
year={2021},
author={Wirth, Claus-Peter},
title={A Most Interesting Draft for Hilbert and Bernays' ``Grundlagen der Mathematik'' that never found its way into any publication, and two CV of Gisbert Hasenjaeger},
publisher={{SEKI Publications, Bremen}},
series={{SEKI-Working-PAPER SWP--2017--01 (ISSN 1860--5931)}},
note={Full paper etc.: \url{https://arxiv.org/abs/1803.01386}. The ``Draft'' mentioned in the title is \cite{bernays-Hs973:41}. 4th edn.\ of June 25, 2021, revised to be in correspondence with the blog ``ETHeritage'' \url{https://etheritage.ethz.ch/2021/06/25/urschriften-zu-hilbert-bernays-grundlagen-der-mathematik/} and the new sub-folder Hs973:41.1 in the ETH-Bibliothek, Hochschularchiv. ii+60pp. 1st edn. March 2018; 2nd thoroughly rev.\ \& largely extd.\ edn.\ Jan.\ 2020; 3rd thoroughly rev.\ \& largely extd.\ edn.\ June 9, 2021},
}

@Unpublished{bernays-Hs973:41,
year={1952(?)},
author={Bernays, Paul
    and Hasenjaeger, Gisbert},
title={A Most Interesting Draft for Hilbert and Bernays' ``Grundlagen der Mathematik''},
note={Unpublished untitled typescript by Hasenjaeger with corrections from Bernays' hand, {34 pp.} with page numbers 2--34 on the respective page headers; ETH-Bibliothek, Hochschularchiv, in Hs973(Paul Bernays):41 (since June 22, 2021, in the new sub-folder Hs973:41.1). Swiss Federal Institute of Technology in Z\"urich (ETH Zurich), Z\"urich (Switzerland). Scan of the typescript: \url{https://etheritage.ethz.ch/wp-content/uploads/2021/05/Hs_973_41_S_1-34.pdf}. Two carbon copies without the corrections from Bernays' hand (however, with most of these corrections executed with a typewriter), but with two extra pages containing the footnotes for the original typescript (which comes only with footnote marks, but without any footnote texts) were found in the Legacy of Gisbert Hasenjaeger, Deutsches Museum, M\"unchen, Archiv: ``Nachl\"asse H, NL288''},
}