00425nam a2200157Ia 4500008004100000020001500041082001600056100002000072245005300092250000600145260004500151300000800196650002300204650001800227653002200245170901s1975    xx            000 0 und d  a0521207088  a589.7bS80N  aStewart, W.D.P. 0aNitrogen fixation by free living micro-organisms  a1  aLondonbCambridge University Pressc1975  a471  aBotanical sciences  aPure Sciences  aNitrogen fixation