@techreport {TR-1990-019,
   type = {Technical Report},
   author = {Stephen Fickas, Rob Helm },
   title = {A Transformational Approach to Composite System Specification},
   institution = {University of Oregon, Computer and Information Sciences Department},
   number = TR-1990-019,
   month = 11,
   year = 1990,
   note = {Available at \url{https://www.cs.uoregon.edu/Reports/TR-1990-019.pdf}},
}