Free Download Lectures on Quasiconformal Mappings… By Lars V. Ahlfors Publisher D. Van Nostrand Company, Inc. 1966 ISBN 0442302673,9780442302672..

Free Download Lectures on quasiconformal mappings… By Lars V. Ahlfors Publisher American Mathematical Society 2006 ISBN 0-8218-3644-7,9780821836446..