00320nam a2200097   450000100070000000500170000700800360002410000330006024500720009326400570016500783520260807101511.0260101s1948    pe      000 0 eng  d1 aSantiago Antúnez de Mayolo10aThe neutral element base of matter and probble cause of gravitation 1aLimabUniversidad Nacional Mayor de San Marcosc1948