Purchasing
https://openalex.org/C2778813691
https://www.wikidata.org/wiki/Q1369832
Stock (firearms)
https://openalex.org/C204036174
https://www.wikidata.org/wiki/Q909380
Stockout
https://openalex.org/C50601946
https://www.wikidata.org/wiki/Q962928
Operations research
https://openalex.org/C42475967
https://www.wikidata.org/wiki/Q194292
Lead time
https://openalex.org/C2781468064
https://www.wikidata.org/wiki/Q1267117
Computer science
https://openalex.org/C41008148
https://www.wikidata.org/wiki/Q21198
Order (exchange)
https://openalex.org/C182306322
https://www.wikidata.org/wiki/Q1779371
Perpetual inventory
https://openalex.org/C194191399
https://www.wikidata.org/wiki/Q7169552
Stock management
https://openalex.org/C150418976
https://www.wikidata.org/wiki/Q3761396
Economics
https://openalex.org/C162324750
https://www.wikidata.org/wiki/Q8134
Operations management
https://openalex.org/C21547014
https://www.wikidata.org/wiki/Q1423657
Business
https://openalex.org/C144133560
https://www.wikidata.org/wiki/Q4830453
Inventory management
https://openalex.org/C3018434026
https://www.wikidata.org/wiki/Q3761396
Providing background information: reference to the literature
A number of recent studies …
[INST] Please produce a sentence from the paper. The sentence should not mention the title of the paper, rather it be extracted from the Discussing Findings section of the paper.
Please provide one singular full sentence from the paper that serves the function provided, using the example as guidance. Be specific, using relevant terminology from the paper.
Refrain from vague or generic statements. Finally produce a search query in the form of a question targeted towards the knowledge contained therein. 
You must output json with the structure of {'Sentence': sentence, 'Query': query}.
Field: "Operations research".
Paper: "Optimal Policies for a Multi-Echelon Inventory Problem"
Function: "Providing background information: reference to the literature".
Example Sentence: "A number of recent studies …". [/INST]