Perhaps you should try some spelling variations:
"an introduction to computer programsrs" » "an introduction to computer programmers" (Expand search), "an introduction to computer programs" (Expand search), "an introduction to computer programmes" (Expand search), "an introduction to compute programsrs" (Expand search), "an introduction _ computer programsrs" (Expand search), "an introduction by computer programsrs" (Expand search), "an introduction to computer programasrs" (Expand search)
"advanced python python computer program" » "advanced method python computer program" (Expand search), "advanced path python computer program" (Expand search), "advanced symphony python computer program" (Expand search), "advanced pythons python computer program" (Expand search), "advanced piton python computer program" (Expand search), "advanced pitons python computer program" (Expand search), "advanced python python computer programa" (Expand search)

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"an introduction to computer programsrs\") OR (\"advanced python python computer program\"))~".
• Removing quotes may allow a broader search: (( an introduction to computer programsrs ) OR ( advanced python python computer program ))~.
• Adding a wildcard symbol may retrieve word variants: (("an introduction to computer programsrs") OR ("advanced python python computer program"))*.