00247nam a22000977a 4500003000400000008004100004082001700045100001400062245003100076260004200107OSt230617b        |||||||| |||| 00| 0 eng d  a589.2bPP447  aUsher, G.  aAn Introduction to Viruses  aT.T.B.A., PatnabAcademic Pressc1970