00285nam a2200097Ia 4500008004100000082001600041100003400057245005200091260003600143300000800179140113s9999    xx            000 0 und d  a581.13   L4  a"Burns, R.C. & Hardy, R.W.F."  aNitrogen fixation in bacteria and higher plants  a1975bSpringer-VerlagcNew York  a189