Reference 160 History 95 Literature & Fiction 73 Philosophy 61 Greek drama 60 Green revolution 60 മലയാളം ;പഠനം; റെഫറന്‍സ് 58 Malayalam ; Study;Referance 57 Literature 56 Children's Books 49 Green movement 48 Reference & Nonfiction 43 Malayalam; Referance 42 മലയാളം; റെഫറന്‍സ് 42 Non Fiction 39 reference 38 Greek literature 37 Green chemistry 37 Greek 31 Green house effect 29 Green technology 29 History and criticism 29 Criticism and interpretation 28 Greek drama (Tragedy) 28 Dissertations, Academic (Ph.D) 27 Economics 24 Drama 22 Environmentalism 22 Criticism 21 Environmental policy 21