Perhaps you should try some spelling variations:
"nonlinear potential theory" » "nonlinear partial theory", "nonlinear material theory", "nonlinear properties theory"
"nonlinear spectral theorem" » "linear spectral theorem", "nonlinear structural theorem", "nonlinear spectral theory"
"nonlinear aspects theorem" » "nonlinear effects theorem", "nonlinear aspects theory", "nonlinear aspects three", "nonlinear aspect theory"

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: (("nonlinear potential theory") OR ((("nonlinear spectral theorem") OR ("nonlinear aspects theorem")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"nonlinear potential theory\") or (((\"nonlinear spectral theorem\") OR (\"nonlinear aspects theorem\"))))".
• Removing quotes may allow a broader search: (( nonlinear potential theory ) or ((( nonlinear spectral theorem ) OR ( nonlinear aspects theorem )))).
• Adding a wildcard symbol may retrieve word variants: (("nonlinear potential theory") or ((("nonlinear spectral theorem") OR ("nonlinear aspects theorem"))))*.