I _need_ J.H.B. Kemperman's 1956 paper _On complexes in a semigroup_, but the online archive of <a href="http://www.sciencedirect.com/science/journal/00193577">_Indagationes Mathematicae_</a>, where it was originally published, goes back until 1990. Are you aware of any comparatively recent reprint or something like that? Thank you much in advance for any help you can provide.