Perhaps you should try some spelling variations:
total poverty » global poverty, rural poverty, national poverty
poverty a » poverty _, poverty data
robust e » robust _, robust end, robust l1
robust a » robust _, robust cat, robust lca
book » ebook
books » ebooks
heitmannn » heitmann, heimann, neitmann

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: (( total poverty a. heilemann book ) OR ( _ ((robust e) OR (robust a)). heitmannn books ))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( total poverty a. heilemann book ) or ( _ ((robust e) OR (robust a)). heitmannn books ))~".
• Adding a wildcard symbol may retrieve word variants: (( total poverty a. heilemann book ) or ( _ ((robust e) OR (robust a)). heitmannn books ))*.