na INLIS000000000004319 20220414104535 0010-1021000023 220414 g 0 eng The biology of agricultural systems / C.R.W. Spedding Spedding, C.R.W. London : Academic Press, 1975 ix, 261 p.: ill.; 23 cm. ; 23 cm. 631 SPE b 631 FARMING SYSTEMS BIOLOGY Incl. Index 593/KA/2021 2112/83