Acknowledgements With pleasure.the author thanks Gary Chartrand for the advice and informatior he kindy suppied on may topics described n this book thanks th iewers for able i and s vided with the first draft of this inally,th because of all of you that an improved book resulted. ix Acknowledgements With pleasure, the author thanks Gary Chartrand for the advice and information he kindly supplied on many topics described in this book. In addition, the author thanks the reviewers for the valuable input and suggestions they provided with the first draft of this manuscript. Finally, the author is very grateful to Razia Amzad, SpringerBriefs editor, for her kindness and encouragement in writing this book. It is because of all of you that an improved book resulted. ix