Automatic text document summarization is active research area in text mining field. In this article, the authors are proposing two new approaches (three models) for sentence selection, and a new entropy-based summary evaluation criteria. The first approach is based on the algebraic model, Singular Value Decomposition (SVD), i.e. Latent Semantic Analysis (LSA) and model is termed as proposed_model-1, and Second Approach is based on entropy that is further divided into proposed_model-2 and proposed_model-3. In first proposed model, the authors are using right singular matrix, and second & third proposed models are based on Shannon entropy. The advantage of these models is that these are not a Length dominating model, giving better results, and low redundancy. Along with these three new models, an entropy-based summary evaluation criteria is proposed and tested. They are also showing that their entropy based proposed models statistically closer to DUC-2002's standard/gold summary. In this article, the authors are using a dataset taken from Document Understanding Conference-2002.