00297nam a2200109 a 450000500170000008200170001710000250003424500460005926000430010530000200014870000190016820251203091011.0  a577.076bWRA  aWratten, Stephen, D.  aField and laboratory exercises in ecology  aBaltimorebUniversity Park Pressc1980  ax, 227p, 22 cm.  aFry, Gary, LA.