Singh , Akhand Pratap Pramukh Bhoutik Vaigyanik aur Unke Aavishkar / by Akhand Pratap Singh - New Delhi : Prasanta Distributor , 2014. - 151 p. ill. ; 22 c.m. ISBN: 9789383963133 Subjects--Topical Terms: Hindi Collection Dewey Class. No.: 530.0922 / SIN / P