The book entitled 'Organic Light Emitting Materials for OLEDs' covers both the theoretical and practical aspects of the chemistry and properties of organic materials and emphasis mostly on the materials based on dibenzophospholes and phosphine oxides. The introduction and the aim of each chapter is given at the start of the chapter. The subject matter has been presented in a very simple language, clear style along with a number of illustrative diagrams where required. As an Author, I personally believe that this book will definitely deliver all necessary information for the benefit of students and researchers in the field of organic electronics.

Use of auxiliary information has been extensively used in survey sampling to increase the precision of the estimates. Ratio and Regression methods are most popular methods that utilizes information of auxiliary attributes. The auxiliary information has also been used in two-phase sampling for estimation of population characteristics. In this book use of auxiliary attributes have been proposed in two-phase sampling. Several methods have been proposed by using information on auxiliary attributes. The generalized ratio and regression families have been suggested. We have also proposed the shrinkage estimators by using information of multiple auxiliary attributes.