@techreport {TR-1991-010,
   type = {Technical Report},
   author = {C. Wilson, M. Santha},
   title = {Polynomial Size Constant Depth Circuits with a Limited Number of Negations},
   institution = {University of Oregon, Computer and Information Sciences Department},
   number = TR-1991-010,
   month = 4,
   year = 1991,
   note = {Available at \url{https://www.cs.uoregon.edu/Reports/TR-1991-010.pdf}},
}