„The book serves well as an introduction and an overview of the subject and a long list of references helps with further study.“ -- Zbl. Math. „The book is well done... should be an essential purchase for mathematics libraries and is likely to be a standard reference for years to come, providing an introduction to an attractive area of further research.“ -- Mathematical Reviews „The importance and actuality of the subject, as well as the very rigorous and didactic presentation of the content, make out of this book a valuable contribution to current mathematics. The book is intended first of all to mathematicians, but it can be interesting also for a wide circle of readers, including mechanicists and physicists.“ -- Mathematica
