Perhaps you should try some spelling variations:
"mixed initial sources" » "mixed initial resources", "mixed critical sources", "mixed initial resource", "mixed martial sources", "mixed initiative sources"
"mixed initial app" » "mixed martial app", "mixed initiative app", "mixed initial art", "mixed initial case", "mixed initial care"

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: (("mixed initial sources") OR ("mixed initial app")).
• Removing quotes may allow a broader search: (( mixed initial sources ) or ( mixed initial app )).
• Adding a wildcard symbol may retrieve word variants: (("mixed initial sources") or ("mixed initial app"))*.