2 joint papers of Lorenz Halbeisen with Shelah

HlSh:699 2000-09-19 [pdf] [ps] [abstract] [arXiv:math.LO/0010268]
Halbeisen+Shelah, Relations between some cardinals in the absence of the Axiom of Choice -- Bulletin Symbolic Logic 7 (2001) 237-261
HlSh:488 1993-08-27 [pdf] [ps] [abstract] [arXiv:math.LO/9308220]
Halbeisen+Shelah, Consequences of arithmetic for Set theory -- J Symbolic Logic 59 (1994) 30-40