Perhaps you should try some spelling variations:
informal transport » informal transfers, affordable transport
transport system » transport sector, transport costs
formal transfer » informal transfers, social transfer, fiscal transfer
de informal » do informal, _ informal, vs informal
transfer em » transfer fee, transfer _, transfer a
system can » systems can, system a, systems case
do formal » do informal, non formal, _ formal

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (( aguas de informal transport system can ) OR ( aguas do formal transfer em cacao ))~.
• Adding a wildcard symbol may retrieve word variants: (( aguas de informal transport system can ) or ( aguas do formal transfer em cacao ))*.