@CONFERENCE\{IMM1997-02342, author = "D. Bj{\o}rner and S. Koussobe and R. Noussi and G. Satchok", title = "Michael Jackson's Problem Frames: Towards Methodological Principles of Selecting and Applying Formal Software Development Techniques and Tools", year = "1997", pages = "263-271", booktitle = "ICFEM'97: Intl. Conf. on ``Formal Engineering Methods{'',} Hiroshima, Japan", volume = "", series = "", editor = "Li ShaoQi and Michael Hinchley", publisher = "{IEEE} Computer Society Press", organization = "", address = "", note = "Invited lecture. \$\backslash\$htmladdnormallinkfoot\{Postscript document\}\{http://www.it.dtu.dk/\verb+~+db/frames/ieeefram.ps\}", url = "http://www2.compute.dtu.dk/pubdb/pubs/2342-full.html" }