00287nam a2200109Ia 4500082001800000100001700018245005300035260000900088300001600097490005900113500000500172  aSA.36 Su948b  aSuits, D. B.  aUse of Dummy variables in regressian equationsb  c1957  app. 548-551  aJournal of American Statistical Association, Dec. 1957  a