00358nam a2200133ua 4500001000700000008004100007082001400048100002100062245004200083260004600125300001100171490001900182650002300201007293181020s1979 ck gr 000 spa d04a503bS5481 aShepherd, Walter13aLa ciencia avanza / cWalter Shepherd aBuenos Aires : bEditorial Losada, c1943 a541 p.0 aCiencia y vida14aCiencias básicas