Perhaps you should try some spelling variations:
transfer functions » transfer function (Expand search), pedotransfer functions (Expand search)
extraction method » extraction methods (Expand search)
basic extraction » based extraction (Expand search), classic extraction (Expand search), based extractions (Expand search)
functions basic » functions based (Expand search), functional basis (Expand search), functions brazil (Expand search)
indigo python » codigo python (Expand search), codigos python (Expand search)
python python » pythons python (Expand search), piton python (Expand search), pitons python (Expand search)

You may be able to get more results by adjusting your search query.

• Removing quotes may allow a broader search: (( transfer functions basic extraction method ) OR ( using indigo python python programming ))~.