Perhaps you should try some spelling variations:
reversions » perversions, revisions, reversing, reversion, reaversion, versions, aversions, diversions
versions » version, aversion
reversion » version, aversion, diversion
recession » regression
regressions » regression
recursion » recursions, recursive, recursos

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((reversions OR versions) or reversion) or (recession or regressions)) or recursion)~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((reversions OR versions) OR reversion) OR (recession OR regressions)) OR recursion).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((reversions OR versions) or reversion) or (recession or regressions)) or recursion)".
• Adding a wildcard symbol may retrieve word variants: ((((reversions OR versions) or reversion) or (recession or regressions)) or recursion)*.