Perhaps you should try some spelling variations:
implementation michael » implementation richard, implementation model, implementation chap
implementation manual » implementation model, implementation a
external python » external pathogen, external action, external persons
python program » python programs, action program, python programming

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

• Performing a fuzzy search may retrieve terms with similar spellings: external python program ((implementation michael) OR (implementation manual)) https~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "external python program ((implementation michael) OR (implementation manual)) https".
• Adding a wildcard symbol may retrieve word variants: external python program ((implementation michael) OR (implementation manual)) https*.