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PREFACE
I am specially indebted to Professor BRUHN who discussed with me the problems connected with this thesis during all the stages of the work. His scholarship and the keen interest he took in my studies have been a constant encouragement.
A fellow-scholar he does not want his name to be mentioned has typed my thesis. The reader who finds the text tolerably intelligible on account of the typographical lay-out will appreciate the care bestowed by the anonymous co-worker on the execution of his difficult task.
I am also grateful to my wife: VASUDHA and my children (son: ASHOK, daughter: NINA) who had to live in India facing difficulties during my stay in Germany.
