Perhaps you should try some spelling variations:
ptask » task, ptas, ptaskk, ptapsk, pptask
ptaskk » taskk, ptask, ptaskkk, ptapskk, pptaskk
rpptask » rptask, rpptas, rpptaskk, rpptapsk, rppptask
rtas » ras, ptas, ftas, rtask, rtaps, rptas
tas » task, taps, ptas
pas » pass, pays, pads
past » passt, payst, padst, east, part

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: ((((ptask OR ptaskk) OR (rtas OR rpptask)) OR (tas OR (pas OR past))) OR rio)-ibg books series.~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((ptask OR ptaskk) or (rtas or rpptask)) or (tas or (pas or past))) or rio)-ibg books series.~".
• Adding a wildcard symbol may retrieve word variants: ((((ptask OR ptaskk) or (rtas or rpptask)) or (tas or (pas or past))) or rio)-ibg books series.*.