1. Aptroot, A. (2000) A contribution to the lichen flora of West Jutland, Denmark, Graphis Scripta 12, 24–28.
2. Aptroot, A. and Boom, P.P.G. van den (1998) Pyrenocollema chlorococcum: a new species with a chlorococcoid photobiont from zinc-contaminated soils and wood, Cryptogamie, Bryologie et Lichénologie 19, 193–196.
3. Aptroot, A. and Brand, A.M. (1996) Lichenen van de voorjaarsexcursie 1995 naar Bramsche, Niedersachsen, Buxbaumiella 39, 41–46.
4. Aptroot, A. and Herk, K. van (1999) Algen, korstmossen en mossen op monumenten, RDMZ info Restoratie en beheer no. 16, also on http://www.lichens.myweb.nl/
5. Aptroot, A. and Sparrius, L.B. (2000) Notes on Thelocarpun citrum (Wallr.) Rossman (syn. T. herteri J. Lahm, T. vicinellum Nyl.) and a report of T. sphaerosporum H. Magn. with pycnidia, both colonizing sandy areas recently stripped of their top soil, Lichenologist 32, 513–514.