@BOOK {HARTLEY:1998,
title = {Tractor design and operation for research stations: IITA research guide, No. 4},
author = {Hartley, P. V. },
series = {IITA research guide, No. 4},
year = {1998},
month = {October},
publisher = {International Institute of Tropical Agriculture (IITA)},
address = {Ibadan Nigeria},
isbn = {978-131-124-X},
note = {29p.},
}