There is a technical presentation titled indexed as item 163 in certain digital libraries like the TIB AV-Portal . 3. RAR (Rest-Activity Rhythms) Research
If you are looking for school materials, is a popular English language series (e.g., by Express Publishing/Prosveshcheniye). Spotlight 163 rar
Knowing if this is for English language homework , a scientific conference , or a technical software module will help me find the exact file or document you need. There is a technical presentation titled indexed as
The .rar extension suggests you might be looking for a downloadable archive of for a specific level. 2. Academic & Technical Papers a scientific conference