proper support for "isabelle update -D DIR": avoid accidental exclusion of select_dirs (amending e5dafe9e120f);
@InProceedings{Avigad-Donnelly,
author = {Jeremy Avigad and Kevin Donnelly},
title = {Formalizing {O} notation in {Isabelle/HOL}},
booktitle = {Automated Reasoning: second international conference, IJCAR 2004},
pages = {357--371},
year = 2004,
editor = {David Basin and Micha\"el Rusiowitch},
publisher = {Springer}
}
@PhdThesis{McMillan-PhDThesis,
author = {Kenneth McMillan},
title = {Symbolic Model Checking --- An Approach to the State Explosion Problem},
school = {Carnegie Mellon University},
year = {1992},
month = {May},
url = {\url{http://mcmil.net/pubs/thesis.pdf}},
}