P.T. Wilrich (Wilrich, P.T. / P. T. Wilrich / Wilrich, P. T.)

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  Frontiers in Stastical Quality Control 5
  by Hans-Joachim Lenz, P.-Th Wilrich, H.J. Lenz, P.T. Wilrich
  Softcover, Springer Verlag, ISBN 3790809845 (3-7908-0984-5)
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  Frontiers in Statistical Quality Control 4
  by G.B. Wetherill, H.J. Lenz, P.T. Wilrich
  Softcover, Springer Verlag, ISBN 038791434X (0-387-91434-X)
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  Frontiers in Statistical Quality Control 6
  by Hans-Joachim Lenz, Peter-Theodor Wilrich
  Softcover, Springer Verlag, ISBN 3790813745 (3-7908-1374-5)
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  Frontiers in Statistical Quality Control, 3
  by H.J. Lenz, G.B. Wetherill, P.T. Wilrich
  Softcover, Springer Verlag, ISBN 0387913157 (0-387-91315-7)