Oswald W. Knauth, and Frederick C. Mills, Directors of the
National Bureau; by J. Steele Gow of The Maurice and Laura
Falk Foundation; by Ernest W. Williams, Jr. of Columbia Uni-
versity; by H. S. Davis of the University of Pennsylvania; and
by Alden F. Bixby of the Railroad Retirement Board.

I have still further obligations. Irving H. Siegel, formerly of
the National Bureau and now with the Veterans Administration,
worked on the project in its early stages. H. Irving Forman drew
the charts with his customary skill. Roselyn Silverman checked
the manuscript in proof. Finally, Martha Anderson suggested
numerous textual improvements, and steered the book through
the press.

The study upon which this volume and the previously issued
reports are based was made possible by funds granted by The
Maurice and Laura Falk Foundation of Pittsburgh. The Falk
Foundation is not, however, the author, publisher or proprietor
of this publication, and is not to be understood as approving or
disapproving by virtue of its grant any of the statements made
or views expressed therein.

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