O-Rings-Global Market Status & Trend Report 2016-2026 Top 20 Countries Data
Report Summary
O-Rings-Global Market Status & Trend Report 2016-2026 Top 20 Countries Data offers a comprehensive analysis on O-Rings industry, standing on the readers’ perspective, delivering detailed market data in Global major 20 countries and penetrating insights. No matter the client is industry insider, potential entrant or investor, the report will provides useful data and information. Key questions answered by this report include:
Worldwide and Top 20 Countries Market Size of O-Rings 2016-2021, and development forecast 2022-2026
Main manufacturers/suppliers of O-Rings worldwide and market share by regions, with company and product introduction, position in the O-Rings market
Market status and development trend of O-Rings by types and applications
Cost and profit status of O-Rings, and marketing status
Market growth drivers and challengesSince the COVID-19 virus outbreak in December 2019, the disease has spread to almost 100 countries around the globe with the World Health Organization declaring it a public health emergency.The global impacts of the coronavirus disease 2019 (COVID-19) are already starting to be felt, and will significantly affect the Ammonium O-Rings market in 2020.COVID-19 can affect the global economy in three main ways: by directly affecting production and demand, by creating supply chain and market disruption, and by its financial impact on firms and financial markets.The outbreak of COVID-19 has brought effects on many aspects, like flight cancellations; travel bans and quarantines; restaurants closed; all indoor events restricted; over forty countries state of emergency declared; massive slowing of the supply chain; stock market volatility; falling business confidence, growing panic among the population, and uncertainty about future.This report also analyses the impact of Coronavirus COVID-19 on the O-Rings industry.
The report segments the global O-Rings market as:
Global O-Rings Market: Regional Segment Analysis (Regional Production Volume, Consumption Volume, Revenue and Growth Rate 2016-2026):
North America (United States, Canada and Mexico)
Europe (Germany, UK, France, Italy, Russia, Spain and Benelux)
Asia Pacific (China, Japan, India, Southeast Asia and Australia)
Latin America (Brazil, Argentina and Colombia)
Middle East and Africa
Global O-Rings Market: Type Segment Analysis (Consumption Volume, Average Price, Revenue, Market Share and Trend 2016-2026):
NitrileRubber
FKMFluoroelastomers
Global O-Rings Market: Application Segment Analysis (Consumption Volume and Market Share 206-2026; Downstream Customers and Market Analysis)
Electrical&ElectronicProducts
AerospaceEquipment
Marine&RailEquipment
Automobile
Global O-Rings Market: Manufacturers Segment Analysis (Company and Product introduction, O-Rings Sales Volume, Revenue, Price and Gross Margin):
FreudenbergSealingTechnologies
BalSealEngineering
FlexitallicGroup
Lamons
SKFGroup
JamesWalker
In a word, the report provides detailed statistics and analysis on the state of the industry; and is a valuable source of guidance and direction for companies and individuals interested in the market.
O-Rings-Global Market Status & Trend Report 2016-2026 Top 20 Countries Data offers a comprehensive analysis on O-Rings industry, standing on the readers’ perspective, delivering detailed market data in Global major 20 countries and penetrating insights. No matter the client is industry insider, potential entrant or investor, the report will provides useful data and information. Key questions answered by this report include:
Worldwide and Top 20 Countries Market Size of O-Rings 2016-2021, and development forecast 2022-2026
Main manufacturers/suppliers of O-Rings worldwide and market share by regions, with company and product introduction, position in the O-Rings market
Market status and development trend of O-Rings by types and applications
Cost and profit status of O-Rings, and marketing status
Market growth drivers and challengesSince the COVID-19 virus outbreak in December 2019, the disease has spread to almost 100 countries around the globe with the World Health Organization declaring it a public health emergency.The global impacts of the coronavirus disease 2019 (COVID-19) are already starting to be felt, and will significantly affect the Ammonium O-Rings market in 2020.COVID-19 can affect the global economy in three main ways: by directly affecting production and demand, by creating supply chain and market disruption, and by its financial impact on firms and financial markets.The outbreak of COVID-19 has brought effects on many aspects, like flight cancellations; travel bans and quarantines; restaurants closed; all indoor events restricted; over forty countries state of emergency declared; massive slowing of the supply chain; stock market volatility; falling business confidence, growing panic among the population, and uncertainty about future.This report also analyses the impact of Coronavirus COVID-19 on the O-Rings industry.
The report segments the global O-Rings market as:
Global O-Rings Market: Regional Segment Analysis (Regional Production Volume, Consumption Volume, Revenue and Growth Rate 2016-2026):
North America (United States, Canada and Mexico)
Europe (Germany, UK, France, Italy, Russia, Spain and Benelux)
Asia Pacific (China, Japan, India, Southeast Asia and Australia)
Latin America (Brazil, Argentina and Colombia)
Middle East and Africa
Global O-Rings Market: Type Segment Analysis (Consumption Volume, Average Price, Revenue, Market Share and Trend 2016-2026):
NitrileRubber
FKMFluoroelastomers
Global O-Rings Market: Application Segment Analysis (Consumption Volume and Market Share 206-2026; Downstream Customers and Market Analysis)
Electrical&ElectronicProducts
AerospaceEquipment
Marine&RailEquipment
Automobile
Global O-Rings Market: Manufacturers Segment Analysis (Company and Product introduction, O-Rings Sales Volume, Revenue, Price and Gross Margin):
FreudenbergSealingTechnologies
BalSealEngineering
FlexitallicGroup
Lamons
SKFGroup
JamesWalker
In a word, the report provides detailed statistics and analysis on the state of the industry; and is a valuable source of guidance and direction for companies and individuals interested in the market.
CHAPTER 1 OVERVIEW OF O-RINGS
1.1 Definition of O-Rings in This Report
1.2 Commercial Types of O-Rings
1.2.1 NitrileRubber
1.2.2 FKMFluoroelastomers
1.3 Downstream Application of O-Rings
1.3.1 Electrical&ElectronicProducts
1.3.2 AerospaceEquipment
1.3.3 Marine&RailEquipment
1.3.4 Automobile
1.4 Development History of O-Rings
1.5 Market Status and Trend of O-Rings 2016-2026
1.5.1 Global O-Rings Market Status and Trend 2016-2026
1.5.2 Regional O-Rings Market Status and Trend 2016-2026
CHAPTER 2 GLOBAL MARKET STATUS AND FORECAST BY REGIONS
2.1 Market Development of O-Rings 2016-2021
2.2 Sales Market of O-Rings by Regions
2.2.1 Sales Volume of O-Rings by Regions
2.2.2 Sales Value of O-Rings by Regions
2.3 Production Market of O-Rings by Regions
2.4 Global Market Forecast of O-Rings 2022-2026
2.4.1 Global Market Forecast of O-Rings 2022-2026
2.4.2 Market Forecast of O-Rings by Regions 2022-2026
CHAPTER 3 GLOBAL MARKET STATUS AND FORECAST BY TYPES
3.1 Sales Volume of O-Rings by Types
3.2 Sales Value of O-Rings by Types
3.3 Market Forecast of O-Rings by Types
CHAPTER 4 GLOBAL MARKET STATUS AND FORECAST BY DOWNSTREAM INDUSTRY
4.1 Global Sales Volume of O-Rings by Downstream Industry
4.2 Global Market Forecast of O-Rings by Downstream Industry
CHAPTER 5 NORTH AMERICA MARKET STATUS BY COUNTRIES, TYPE, MANUFACTURERS AND DOWNSTREAM INDUSTRY
5.1 North America O-Rings Market Status by Countries
5.1.1 North America O-Rings Sales by Countries (2016-2021)
5.1.2 North America O-Rings Revenue by Countries (2016-2021)
5.1.3 United States O-Rings Market Status (2016-2021)
5.1.4 Canada O-Rings Market Status (2016-2021)
5.1.5 Mexico O-Rings Market Status (2016-2021)
5.2 North America O-Rings Market Status by Manufacturers
5.3 North America O-Rings Market Status by Type (2016-2021)
5.3.1 North America O-Rings Sales by Type (2016-2021)
5.3.2 North America O-Rings Revenue by Type (2016-2021)
5.4 North America O-Rings Market Status by Downstream Industry (2016-2021)
CHAPTER 6 EUROPE MARKET STATUS BY COUNTRIES, TYPE, MANUFACTURERS AND DOWNSTREAM INDUSTRY
6.1 Europe O-Rings Market Status by Countries
6.1.1 Europe O-Rings Sales by Countries (2016-2021)
6.1.2 Europe O-Rings Revenue by Countries (2016-2021)
6.1.3 Germany O-Rings Market Status (2016-2021)
6.1.4 UK O-Rings Market Status (2016-2021)
6.1.5 France O-Rings Market Status (2016-2021)
6.1.6 Italy O-Rings Market Status (2016-2021)
6.1.7 Russia O-Rings Market Status (2016-2021)
6.1.8 Spain O-Rings Market Status (2016-2021)
6.1.9 Benelux O-Rings Market Status (2016-2021)
6.2 Europe O-Rings Market Status by Manufacturers
6.3 Europe O-Rings Market Status by Type (2016-2021)
6.3.1 Europe O-Rings Sales by Type (2016-2021)
6.3.2 Europe O-Rings Revenue by Type (2016-2021)
6.4 Europe O-Rings Market Status by Downstream Industry (2016-2021)
CHAPTER 7 ASIA PACIFIC MARKET STATUS BY COUNTRIES, TYPE, MANUFACTURERS AND DOWNSTREAM INDUSTRY
7.1 Asia Pacific O-Rings Market Status by Countries
7.1.1 Asia Pacific O-Rings Sales by Countries (2016-2021)
7.1.2 Asia Pacific O-Rings Revenue by Countries (2016-2021)
7.1.3 China O-Rings Market Status (2016-2021)
7.1.4 Japan O-Rings Market Status (2016-2021)
7.1.5 India O-Rings Market Status (2016-2021)
7.1.6 Southeast Asia O-Rings Market Status (2016-2021)
7.1.7 Australia O-Rings Market Status (2016-2021)
7.2 Asia Pacific O-Rings Market Status by Manufacturers
7.3 Asia Pacific O-Rings Market Status by Type (2016-2021)
7.3.1 Asia Pacific O-Rings Sales by Type (2016-2021)
7.3.2 Asia Pacific O-Rings Revenue by Type (2016-2021)
7.4 Asia Pacific O-Rings Market Status by Downstream Industry (2016-2021)
CHAPTER 8 LATIN AMERICA MARKET STATUS BY COUNTRIES, TYPE, MANUFACTURERS AND DOWNSTREAM INDUSTRY
8.1 Latin America O-Rings Market Status by Countries
8.1.1 Latin America O-Rings Sales by Countries (2016-2021)
8.1.2 Latin America O-Rings Revenue by Countries (2016-2021)
8.1.3 Brazil O-Rings Market Status (2016-2021)
8.1.4 Argentina O-Rings Market Status (2016-2021)
8.1.5 Colombia O-Rings Market Status (2016-2021)
8.2 Latin America O-Rings Market Status by Manufacturers
8.3 Latin America O-Rings Market Status by Type (2016-2021)
8.3.1 Latin America O-Rings Sales by Type (2016-2021)
8.3.2 Latin America O-Rings Revenue by Type (2016-2021)
8.4 Latin America O-Rings Market Status by Downstream Industry (2016-2021)
CHAPTER 9 MIDDLE EAST AND AFRICA MARKET STATUS BY COUNTRIES, TYPE, MANUFACTURERS AND DOWNSTREAM INDUSTRY
9.1 Middle East and Africa O-Rings Market Status by Countries
9.1.1 Middle East and Africa O-Rings Sales by Countries (2016-2021)
9.1.2 Middle East and Africa O-Rings Revenue by Countries (2016-2021)
9.1.3 Middle East O-Rings Market Status (2016-2021)
9.1.4 Africa O-Rings Market Status (2016-2021)
9.2 Middle East and Africa O-Rings Market Status by Manufacturers
9.3 Middle East and Africa O-Rings Market Status by Type (2016-2021)
9.3.1 Middle East and Africa O-Rings Sales by Type (2016-2021)
9.3.2 Middle East and Africa O-Rings Revenue by Type (2016-2021)
9.4 Middle East and Africa O-Rings Market Status by Downstream Industry (2016-2021)
CHAPTER 10 MARKET DRIVING FACTOR ANALYSIS OF O-RINGS
10.1 Global Economy Situation and Trend Overview
10.2 O-Rings Downstream Industry Situation and Trend Overview
CHAPTER 11 O-RINGS MARKET COMPETITION STATUS BY MAJOR MANUFACTURERS
11.1 Production Volume of O-Rings by Major Manufacturers
11.2 Production Value of O-Rings by Major Manufacturers
11.3 Basic Information of O-Rings by Major Manufacturers
11.3.1 Headquarters Location and Established Time of O-Rings Major Manufacturer
11.3.2 Employees and Revenue Level of O-Rings Major Manufacturer
11.4 Market Competition News and Trend
11.4.1 Merger, Consolidation or Acquisition News
11.4.2 Investment or Disinvestment News
11.4.3 New Product Development and Launch
CHAPTER 12 O-RINGS MAJOR MANUFACTURERS INTRODUCTION AND MARKET DATA
12.1 FreudenbergSealingTechnologies
12.1.1 Company profile
12.1.2 Representative O-Rings Product
12.1.3 O-Rings Sales, Revenue, Price and Gross Margin of FreudenbergSealingTechnologies
12.2 BalSealEngineering
12.2.1 Company profile
12.2.2 Representative O-Rings Product
12.2.3 O-Rings Sales, Revenue, Price and Gross Margin of BalSealEngineering
12.3 FlexitallicGroup
12.3.1 Company profile
12.3.2 Representative O-Rings Product
12.3.3 O-Rings Sales, Revenue, Price and Gross Margin of FlexitallicGroup
12.4 Lamons
12.4.1 Company profile
12.4.2 Representative O-Rings Product
12.4.3 O-Rings Sales, Revenue, Price and Gross Margin of Lamons
12.5 SKFGroup
12.5.1 Company profile
12.5.2 Representative O-Rings Product
12.5.3 O-Rings Sales, Revenue, Price and Gross Margin of SKFGroup
12.6 JamesWalker
12.6.1 Company profile
12.6.2 Representative O-Rings Product
12.6.3 O-Rings Sales, Revenue, Price and Gross Margin of JamesWalker
CHAPTER 13 UPSTREAM AND DOWNSTREAM MARKET ANALYSIS OF O-RINGS
13.1 Industry Chain of O-Rings
13.2 Upstream Market and Representative Companies Analysis
13.3 Downstream Market and Representative Companies Analysis
CHAPTER 14 COST AND GROSS MARGIN ANALYSIS OF O-RINGS
14.1 Cost Structure Analysis of O-Rings
14.2 Raw Materials Cost Analysis of O-Rings
14.3 Labor Cost Analysis of O-Rings
14.4 Manufacturing Expenses Analysis of O-Rings
CHAPTER 15 REPORT CONCLUSION
CHAPTER 16 RESEARCH METHODOLOGY AND REFERENCE
16.1 Methodology/Research Approach
16.1.1 Research Programs/Design
16.1.2 Market Size Estimation
16.1.3 Market Breakdown and Data Triangulation
16.2 Data Source
16.2.1 Secondary Sources
16.2.2 Primary Sources
16.3 Reference
1.1 Definition of O-Rings in This Report
1.2 Commercial Types of O-Rings
1.2.1 NitrileRubber
1.2.2 FKMFluoroelastomers
1.3 Downstream Application of O-Rings
1.3.1 Electrical&ElectronicProducts
1.3.2 AerospaceEquipment
1.3.3 Marine&RailEquipment
1.3.4 Automobile
1.4 Development History of O-Rings
1.5 Market Status and Trend of O-Rings 2016-2026
1.5.1 Global O-Rings Market Status and Trend 2016-2026
1.5.2 Regional O-Rings Market Status and Trend 2016-2026
CHAPTER 2 GLOBAL MARKET STATUS AND FORECAST BY REGIONS
2.1 Market Development of O-Rings 2016-2021
2.2 Sales Market of O-Rings by Regions
2.2.1 Sales Volume of O-Rings by Regions
2.2.2 Sales Value of O-Rings by Regions
2.3 Production Market of O-Rings by Regions
2.4 Global Market Forecast of O-Rings 2022-2026
2.4.1 Global Market Forecast of O-Rings 2022-2026
2.4.2 Market Forecast of O-Rings by Regions 2022-2026
CHAPTER 3 GLOBAL MARKET STATUS AND FORECAST BY TYPES
3.1 Sales Volume of O-Rings by Types
3.2 Sales Value of O-Rings by Types
3.3 Market Forecast of O-Rings by Types
CHAPTER 4 GLOBAL MARKET STATUS AND FORECAST BY DOWNSTREAM INDUSTRY
4.1 Global Sales Volume of O-Rings by Downstream Industry
4.2 Global Market Forecast of O-Rings by Downstream Industry
CHAPTER 5 NORTH AMERICA MARKET STATUS BY COUNTRIES, TYPE, MANUFACTURERS AND DOWNSTREAM INDUSTRY
5.1 North America O-Rings Market Status by Countries
5.1.1 North America O-Rings Sales by Countries (2016-2021)
5.1.2 North America O-Rings Revenue by Countries (2016-2021)
5.1.3 United States O-Rings Market Status (2016-2021)
5.1.4 Canada O-Rings Market Status (2016-2021)
5.1.5 Mexico O-Rings Market Status (2016-2021)
5.2 North America O-Rings Market Status by Manufacturers
5.3 North America O-Rings Market Status by Type (2016-2021)
5.3.1 North America O-Rings Sales by Type (2016-2021)
5.3.2 North America O-Rings Revenue by Type (2016-2021)
5.4 North America O-Rings Market Status by Downstream Industry (2016-2021)
CHAPTER 6 EUROPE MARKET STATUS BY COUNTRIES, TYPE, MANUFACTURERS AND DOWNSTREAM INDUSTRY
6.1 Europe O-Rings Market Status by Countries
6.1.1 Europe O-Rings Sales by Countries (2016-2021)
6.1.2 Europe O-Rings Revenue by Countries (2016-2021)
6.1.3 Germany O-Rings Market Status (2016-2021)
6.1.4 UK O-Rings Market Status (2016-2021)
6.1.5 France O-Rings Market Status (2016-2021)
6.1.6 Italy O-Rings Market Status (2016-2021)
6.1.7 Russia O-Rings Market Status (2016-2021)
6.1.8 Spain O-Rings Market Status (2016-2021)
6.1.9 Benelux O-Rings Market Status (2016-2021)
6.2 Europe O-Rings Market Status by Manufacturers
6.3 Europe O-Rings Market Status by Type (2016-2021)
6.3.1 Europe O-Rings Sales by Type (2016-2021)
6.3.2 Europe O-Rings Revenue by Type (2016-2021)
6.4 Europe O-Rings Market Status by Downstream Industry (2016-2021)
CHAPTER 7 ASIA PACIFIC MARKET STATUS BY COUNTRIES, TYPE, MANUFACTURERS AND DOWNSTREAM INDUSTRY
7.1 Asia Pacific O-Rings Market Status by Countries
7.1.1 Asia Pacific O-Rings Sales by Countries (2016-2021)
7.1.2 Asia Pacific O-Rings Revenue by Countries (2016-2021)
7.1.3 China O-Rings Market Status (2016-2021)
7.1.4 Japan O-Rings Market Status (2016-2021)
7.1.5 India O-Rings Market Status (2016-2021)
7.1.6 Southeast Asia O-Rings Market Status (2016-2021)
7.1.7 Australia O-Rings Market Status (2016-2021)
7.2 Asia Pacific O-Rings Market Status by Manufacturers
7.3 Asia Pacific O-Rings Market Status by Type (2016-2021)
7.3.1 Asia Pacific O-Rings Sales by Type (2016-2021)
7.3.2 Asia Pacific O-Rings Revenue by Type (2016-2021)
7.4 Asia Pacific O-Rings Market Status by Downstream Industry (2016-2021)
CHAPTER 8 LATIN AMERICA MARKET STATUS BY COUNTRIES, TYPE, MANUFACTURERS AND DOWNSTREAM INDUSTRY
8.1 Latin America O-Rings Market Status by Countries
8.1.1 Latin America O-Rings Sales by Countries (2016-2021)
8.1.2 Latin America O-Rings Revenue by Countries (2016-2021)
8.1.3 Brazil O-Rings Market Status (2016-2021)
8.1.4 Argentina O-Rings Market Status (2016-2021)
8.1.5 Colombia O-Rings Market Status (2016-2021)
8.2 Latin America O-Rings Market Status by Manufacturers
8.3 Latin America O-Rings Market Status by Type (2016-2021)
8.3.1 Latin America O-Rings Sales by Type (2016-2021)
8.3.2 Latin America O-Rings Revenue by Type (2016-2021)
8.4 Latin America O-Rings Market Status by Downstream Industry (2016-2021)
CHAPTER 9 MIDDLE EAST AND AFRICA MARKET STATUS BY COUNTRIES, TYPE, MANUFACTURERS AND DOWNSTREAM INDUSTRY
9.1 Middle East and Africa O-Rings Market Status by Countries
9.1.1 Middle East and Africa O-Rings Sales by Countries (2016-2021)
9.1.2 Middle East and Africa O-Rings Revenue by Countries (2016-2021)
9.1.3 Middle East O-Rings Market Status (2016-2021)
9.1.4 Africa O-Rings Market Status (2016-2021)
9.2 Middle East and Africa O-Rings Market Status by Manufacturers
9.3 Middle East and Africa O-Rings Market Status by Type (2016-2021)
9.3.1 Middle East and Africa O-Rings Sales by Type (2016-2021)
9.3.2 Middle East and Africa O-Rings Revenue by Type (2016-2021)
9.4 Middle East and Africa O-Rings Market Status by Downstream Industry (2016-2021)
CHAPTER 10 MARKET DRIVING FACTOR ANALYSIS OF O-RINGS
10.1 Global Economy Situation and Trend Overview
10.2 O-Rings Downstream Industry Situation and Trend Overview
CHAPTER 11 O-RINGS MARKET COMPETITION STATUS BY MAJOR MANUFACTURERS
11.1 Production Volume of O-Rings by Major Manufacturers
11.2 Production Value of O-Rings by Major Manufacturers
11.3 Basic Information of O-Rings by Major Manufacturers
11.3.1 Headquarters Location and Established Time of O-Rings Major Manufacturer
11.3.2 Employees and Revenue Level of O-Rings Major Manufacturer
11.4 Market Competition News and Trend
11.4.1 Merger, Consolidation or Acquisition News
11.4.2 Investment or Disinvestment News
11.4.3 New Product Development and Launch
CHAPTER 12 O-RINGS MAJOR MANUFACTURERS INTRODUCTION AND MARKET DATA
12.1 FreudenbergSealingTechnologies
12.1.1 Company profile
12.1.2 Representative O-Rings Product
12.1.3 O-Rings Sales, Revenue, Price and Gross Margin of FreudenbergSealingTechnologies
12.2 BalSealEngineering
12.2.1 Company profile
12.2.2 Representative O-Rings Product
12.2.3 O-Rings Sales, Revenue, Price and Gross Margin of BalSealEngineering
12.3 FlexitallicGroup
12.3.1 Company profile
12.3.2 Representative O-Rings Product
12.3.3 O-Rings Sales, Revenue, Price and Gross Margin of FlexitallicGroup
12.4 Lamons
12.4.1 Company profile
12.4.2 Representative O-Rings Product
12.4.3 O-Rings Sales, Revenue, Price and Gross Margin of Lamons
12.5 SKFGroup
12.5.1 Company profile
12.5.2 Representative O-Rings Product
12.5.3 O-Rings Sales, Revenue, Price and Gross Margin of SKFGroup
12.6 JamesWalker
12.6.1 Company profile
12.6.2 Representative O-Rings Product
12.6.3 O-Rings Sales, Revenue, Price and Gross Margin of JamesWalker
CHAPTER 13 UPSTREAM AND DOWNSTREAM MARKET ANALYSIS OF O-RINGS
13.1 Industry Chain of O-Rings
13.2 Upstream Market and Representative Companies Analysis
13.3 Downstream Market and Representative Companies Analysis
CHAPTER 14 COST AND GROSS MARGIN ANALYSIS OF O-RINGS
14.1 Cost Structure Analysis of O-Rings
14.2 Raw Materials Cost Analysis of O-Rings
14.3 Labor Cost Analysis of O-Rings
14.4 Manufacturing Expenses Analysis of O-Rings
CHAPTER 15 REPORT CONCLUSION
CHAPTER 16 RESEARCH METHODOLOGY AND REFERENCE
16.1 Methodology/Research Approach
16.1.1 Research Programs/Design
16.1.2 Market Size Estimation
16.1.3 Market Breakdown and Data Triangulation
16.2 Data Source
16.2.1 Secondary Sources
16.2.2 Primary Sources
16.3 Reference
