GB standards are the China national standards; Prefix code GB are Mandatory standards, GB/T are Recommended standards; All products or service must be compliance with GB standards; If you want to export products or services to huge Chinese market, need ensure they are meet the requirements of GB china national standards; We provide Chinese GB standards and English version GB standards Lookup, Translate, Download, Imported Commodity GB standards Testing and Compliance review services. |
Standard Code | Standard Title | Standard Class | Order |
---|---|---|---|
GB/T 2423.18-2021 |
Environmental testing—Part 2: Test methods—Test Kb:Salt Mist, cyclic(sodium chloride solution) 环境试验 第2部分:试验方法 试验Kb:盐雾,交变(氯化钠溶液) |
China National Standards Mi |
English PDF |
GB/T 22148.3-2021 |
Test method on electromagnetic eMissions—Part 3:Electronic control gear for LED modules 电磁发射的试验方法 第3部分:LED模块用电子控制装置 |
China National Standards Mi |
English PDF |
GB/T 20373-2021 |
DeterMination of acetyl content in modified starch—Titrimetric method 变性淀粉中乙酰基含量的测定 滴定法 |
China National Standards Mi |
English PDF |
GB/T 18341-2021 |
Specifications of survey for geological and Mineral resources exploration 地质矿产勘查测量规范 |
China National Standards Mi |
English PDF |
GB/T 39885-2021 |
ExaMination methods for triazolam in suspected drugs - Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中三唑仑检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39884-2021 |
ExaMination methods for three components in cannabis in suspected drugs - Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中大麻三种成分检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39883-2021 |
ExaMination methods for morphine in suspected drugs - Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中吗啡检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39882-2021 |
ExaMination methods for methylene dioxymetham phetamine in suspected drugs -- Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中二亚甲基双氧安非他明检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39881-2021 |
ExaMination methods for methaqualone in suspected drugs -- Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中安眠酮检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39880-2021 |
ExaMination methods for methadone in suspected drugs -- Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中美沙酮检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39879-2021 |
ExaMination methods for five components in opium in suspected drugs - Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中鸦片五种成分检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39878-2021 |
ExaMination methods for estazolam in suspected drugs - Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中艾司唑仑检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39877-2021 |
ExaMination methods for diazepam in suspected drugs—Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中地西泮检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39876-2021 |
ExaMination methods for cocaine in suspected drugs—Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中可卡因检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39875-2021 |
ExaMination methods for chlordiazepoxide in suspected drugs—Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中氯氮卓检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39874-2021 |
ExaMination methods for bromazepam in suspected drugs—Gas chromatography and gas chromatography-mass spectrometry 疑似毒品中溴西泮检验 气相色谱和气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 21548-2021 |
Methods of measurement of the high speed seMiconductor lasers directly modulated for optical fiber communication systems 光通信用高速直接调制半导体激光器的测量方法 |
China National Standards Mi |
English PDF |
GB/T 15972.42-2021 |
Specifications for optical fibre test methods—Part 42:Measurement methods and test procedures for transMission characteristics—Chromatic dispersion 光纤试验方法规范 第42部分:传输特性的测量方法和试验程序 波长色散 |
China National Standards Mi |
English PDF |
GB 24427-2021 |
Content liMitation of mercury, cadmium and lead for zinc anode primary battery 锌负极原电池汞镉铅含量的限制要求 |
China National Standards Mi |
English PDF |
GB/T 40089-2021 |
Steel wire ropes for the petroleum and natural gas industries—Minimum requirements and terms of acceptance 石油和天然气工业用钢丝绳 最低要求和验收条件 |
China National Standards Mi |
English PDF |
GB/T 40079-2021 |
Classification system and qualification procedures for fugitive eMission type testing of valves 阀门逸散性试验分类和鉴定程序 |
China National Standards Mi |
English PDF |
GB/T 40062-2021 |
Method for deterMination of total inorganic chloride in denatured fuel ethanol and fuel ethanol—Ion chromatography 变性燃料乙醇和燃料乙醇中总无机氯的测定方法 离子色谱法 |
China National Standards Mi |
English PDF |
GB/T 40031-2021 |
DeterMination of medium chain chlorinated paraffins in electrical and electronic products 电子电气产品中多氯化萘的测定 气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 40030-2021 |
DeterMination of medium chain chlorinated paraffins in electrical and electronic products 电子电气产品中中链氯化石蜡的检测方法 |
China National Standards Mi |
English PDF |
GB/T 40027-2021 |
Information technology—Information device interconnection—TerMinal device profile description of smart home electronics system 信息技术 信息设备互连 智能家用电子系统终端设备属性描述 |
China National Standards Mi |
English PDF |
GB/T 40012-2021 |
CustoMization—Taxonomy guideline 个性化定制 分类指南 |
China National Standards Mi |
English PDF |
GB/T 40008.1-2021 |
Performance evaluation and calculating method for water heater system—Part 1:Household and siMilar water heater system 热水制备系统绩效评价与计算方法 第1部分:户用及类似用途热水制备系统 |
China National Standards Mi |
English PDF |
GB/T 39999-2021 |
DeterMination of 15 kinds of prohibited quinolone-type antibiotics in cosmetics including enrofloxacin—Liquid chromatography-tandem mass spectrometry 化妆品中恩诺沙星等15种禁用喹诺酮类抗生素的测定 液相色谱-串联质谱法 |
China National Standards Mi |
English PDF |
GB/T 39998-2021 |
Paper, board and paper products—DeterMination of alkylphenol polyethoxylates—HPLC-MS method 纸、纸板和纸制品 烷基苯酚聚氧乙烯醚类的测定 高效液相色谱质谱法 |
China National Standards Mi |
English PDF |
GB/T 39996-2021 |
Fireworks and firecrackers—DeterMination of calorific value of pyrotechnic powder 烟花爆竹 烟火药发热量的测定 |
China National Standards Mi |
English PDF |
GB/T 39995-2021 |
DeterMination of sterols 甾醇类物质的测定 |
China National Standards Mi |
English PDF |
GB/T 39994-2021 |
DeterMination of six metal elements (iron, calcium, magnesium, zinc, titanium,copper) in polyolefin pipe system 聚烯烃管道中六种金属元素(铁、钙、镁、锌、钛、铜)的测定 |
China National Standards Mi |
English PDF |
GB/T 39993-2021 |
DeterMination of permitted preservatives dimethyl oxazolidine, 7-ethylbicyclooxazolidine and 5-bromo-5-nitro-1,3-dioxane in cosmetics 化妆品中限用防腐剂二甲基噁唑烷、7-乙基双环噁唑烷和5-溴-5-硝基-1,3-二噁烷的测定 |
China National Standards Mi |
English PDF |
GB/T 39986-2021 |
Pumps—Testing—Submersible Mixers for wasterwater and similar applications 泵 试验 污水和类似应用的潜水搅拌器 |
China National Standards Mi |
English PDF |
GB/T 39950-2021 |
AluMina ceramic heat radiating element for LED lamp LED灯用氧化铝陶瓷散热元件 |
China National Standards Mi |
English PDF |
GB/T 39915-2021 |
EpideMic prevention criteria for animal breeding farm 动物饲养场防疫准则 |
China National Standards Mi |
English PDF |
GB/T 39652.4-2021 |
Emergency response guideline for transportation of dangerous goods—Part 4:List of substance which in contact with water eMit toxic gases 危险货物运输应急救援指南 第4部分:遇水反应产生毒性气体的物质目录 |
China National Standards Mi |
English PDF |
GB/T 33351.2-2021 |
DeterMination of arsenic,beryllium,antimony in electrical and electronic products—Part 2:Inductively coupled plasma optical emission spectrometry 电子电气产品中砷、铍、锑的测定 第2部分:电感耦合等离子体发射光谱法 |
China National Standards Mi |
English PDF |
GB/T 27021.9-2021 |
ConforMity assessment-Requirements for bodies providing audit and certification of management systems-Part 9:Competence requirements for auditing and certification of anti-bribery management systems 合格评定 管理体系审核认证机构要求 第9部分:反贿赂管理体系审核与认证能力要求 |
China National Standards Mi |
English PDF |
GB/T 27021.10-2021 |
ConforMity assessment—Requirements for bodies providing audit and certification of management systems—Part 10:Competence requirements for auditing and certification of occupational health and safety management systems 合格评定 管理体系审核认证机构要求 第10部分:职业健康安全管理体系审核与认证能力要求 |
China National Standards Mi |
English PDF |
GB/T 26667-2021 |
TerMinology for electromagnetic shielding materials 电磁屏蔽材料术语 |
China National Standards Mi |
English PDF |
GB/T 22683-2021 |
Methods used to designate model of controls for household and siMilar use 家用和类似用途控制器产品型号编制方法 |
China National Standards Mi |
English PDF |
GB/T 19924-2021 |
Mobile cranes-DeterMination of stability 流动式起重机 稳定性的确定 |
China National Standards Mi |
English PDF |
GB/T 15972.45-2021 |
Specifications for optical fibre test methods—Part 45:Measurement methods and test procedures for transMission characteristics—Mode field diameter 光纤试验方法规范 第45部分:传输特性的测量方法和试验程序 模场直径 |
China National Standards Mi |
English PDF |
GB/T 15972.43-2021 |
Specifications for optical fibre test methods—Part 43: Measurement methods and test procedures for transMission characteristics—Numerical aperture 光纤试验方法规范 第43部分:传输特性的测量方法和试验程序 数值孔径 |
China National Standards Mi |
English PDF |
GB/T 15972.41-2021 |
Specifications for optical fibre test methods-Part 41:Measurement methods and test procedures for transMission characteristics-Bandwidth 光纤试验方法规范 第41部分:传输特性的测量方法和试验程序 带宽 |
China National Standards Mi |
English PDF |
GB/T 11640-2021 |
Seamless aluMinum alloy gas cylinders 铝合金无缝气瓶 |
China National Standards Mi |
English PDF |
GB/T 11066.11-2021 |
Methods for cheMical analysis of gold-Part 11:Determination of magnesium,chromium,manganese,iron,nickel copper,palladium,silver,tin,antimony,lead and bismuth contents-Inductively coupled plasma mass spectrometry 金化学分析方法 第11部分:镁、铬、锰、铁、镍、铜、钯、银、锡、锑、铅和铋含量的测定 电感耦合等离子体质谱法 |
China National Standards Mi |
English PDF |
GB/T 9966.18-2021 |
Test methods for natural stone-Part 18:Petrographic exaMination 天然石材试验方法 第18部分:岩相分析 |
China National Standards Mi |
English PDF |
GB/T 9966.17-2021 |
Test methods for natural stone-Part 17:DeterMination of resistance to salt crystallization 天然石材试验方法 第17部分:盐结晶强度的测定 |
China National Standards Mi |
English PDF |
GB/T 9966.16-2021 |
Test methods for natural stone- Part 16:DeterMination of linear thermal expansion coefficient 天然石材试验方法 第16部分:线性热膨胀系数的测定 |
China National Standards Mi |
English PDF |
GB/T 9966.15-2021 |
Test methods for natural stone- Part 15:DeterMination of resistance ageing by salt mist 天然石材试验方法 第15部分:耐盐雾老化强度测定 |
China National Standards Mi |
English PDF |
GB/T 9966.14-2021 |
Test methods for natural stone-Part 14:DeterMination of rupture energy 天然石材试验方法 第14部分:耐断裂能量的测定 |
China National Standards Mi |
English PDF |
GB/T 9966.12-2021 |
Test methods for natural stone-Part 12:DeterMination of static elastic modulus 天然石材试验方法 第12部分:静态弹性模数的测定 |
China National Standards Mi |
English PDF |
GB/T 9966.10-2021 |
Test methods for natural stone-Part 10:DeterMination of resistance to shaking for individual stone anchoragest 天然石材试验方法 第10部分:挂件组合单元抗震性能的测定 |
China National Standards Mi |
English PDF |
GB/T 9790-2021 |
Metallic materials—Vickers and Knoop Microhardness tests of metallic and other inorganic coatings 金属材料 金属及其他无机覆盖层的维氏和努氏显微硬度试验 |
China National Standards Mi |
English PDF |
GB/T 8151.24-2021 |
Methods for cheMical analysis of zinc concentrates—Part 24:Determination of soluble zinc content—Flame atomic absorption spectrometry 锌精矿化学分析方法 第24部分:可溶性锌含量的测定 火焰原子吸收光谱法 |
China National Standards Mi |
English PDF |
GB/T 6809.12-2021 |
Reciprocating internal combustion engines—Vocabulary of components and systems—Part 12:Exhaust eMission control systems 往复式内燃机 零部件和系统术语 第12部分:排放控制系统 |
China National Standards Mi |
English PDF |
GB/T 3883.309-2021 |
Safety of motor-operated hand-held, transportable and garden tools - Part 309: Particular requirements for transportable Mitre saws 手持式、可移式电动工具和园林工具的安全 第309部分:可移式斜切锯的专用要求 |
China National Standards Mi |
English PDF |
GB/T 2900.36-2021 |
Electrotechnical terMinology—Electric traction 电工术语 电力牵引 |
China National Standards Mi |
English PDF |
GB/T 17650.2-2021 |
Test on gases evolved during combustion of materials from cables or optical fiber cables - Part 2: DeterMination of acidity (by pH measurement) and conductivity 取自电缆或光缆的材料燃烧时释出气体的试验方法 第2部分:酸度(用pH测量)和电导率的测定 |
China National Standards Mi |
English PDF |
GB/T 17650.1-2021 |
Test on gases evolved during combustion of materials from cables or optical fiber cables-Part 1:DeterMination of the halogen acid gas content 取自电缆或光缆的材料燃烧时释出气体的试验方法 第1部分:卤酸气体总量的测定 |
China National Standards Mi |
English PDF |
GB/T 28022-2021 |
Age deterMination guidelines for toys 玩具适用年龄判定指南 |
China National Standards Mi |
English PDF |
GB/T 39826-2021 |
Fine ceraMics—Determining flexural bond strength—Four-point bending method 精细陶瓷 界面弯曲强度测定 四点弯曲法 |
China National Standards Mi |
English PDF |
GB/T 39794.2-2021 |
Test method for wind uplift resistance of mental roof—Part 2:DynaMic pressure method 金属屋面抗风掀性能检测方法 第2部分:动态压力法 |
China National Standards Mi |
English PDF |
GB/T 20218-2021 |
Biaxially oriented polyaMide (nylon) film 双向拉伸聚酰胺(尼龙)薄膜 |
China National Standards Mi |
English PDF |
GB/T 39824-2021 |
DeterMination of relative strength of dyes in solution 溶液中染料相对强度的测定 |
China National Standards Mi |
English PDF |
GB/T 39748.9-2021 |
Urine-absorbing aids for incontinence—Test methods for characterizing polymer-based absorbent materials—Part 9:Gravimetric deterMination of density 失禁用尿吸收辅助器具 聚合物基质吸液材料特性的测试方法 第9部分:称重法测定密度 |
China National Standards Mi |
English PDF |
GB/T 39748.8-2021 |
Urine-absorbing aids for incontinence—Test methods for characterizing polymer-based absorbent materials—Part 8:Gravimetric deterMination of flowrate 失禁用尿吸收辅助器具 聚合物基质吸液材料特性的测试方法 第8部分:称重法测定流量 |
China National Standards Mi |
English PDF |
GB/T 39748.7-2021 |
Urine-absorbing aids for incontinence—Test methods for characterizing polymer-based absorbent materials—Part 7:Gravimetric deterMination of absorption under pressure 失禁用尿吸收辅助器具 聚合物基质吸液材料特性的测试方法 第7部分:称重法测定压力作用下的吸液量 |
China National Standards Mi |
English PDF |
GB/T 39748.6-2021 |
Urine-absorbing aids for incontinence—Test methods for characterizing polymer-based absorbent materials—Part 6:Gravimetric deterMination of fluid retention capacity in saline solution after centrifugation 失禁用尿吸收辅助器具 聚合物基质吸液材料特性的测试方法 第 6 部分: 称重法测定离心后的生理盐水保液率 |
China National Standards Mi |
English PDF |
GB/T 39748.11-2021 |
Urine-absorbing aids for incontinence—Test methods for characterizing polymer-based absorbent materials—Part 11:DeterMination of content of respirable particles 失禁用尿吸收辅助器具 聚合物基质吸液材料特性的测试方法 第11部分:可吸入颗粒含量的测定 |
China National Standards Mi |
English PDF |
GB/T 39748.10-2021 |
Urine-absorbing aids for incontinence -- Test methods for characterizing polymer-based absorbent materials -- Part 10: DeterMination of extractable polymer content by potentiometric titration 失禁用尿吸收辅助器具 聚合物基质吸液材料特性的测定方法 第10部分:电位滴定法测定可萃取聚合物量 |
China National Standards Mi |
English PDF |
GB/T 4214.9-2021 |
Test method for noise of household and siMilar electrical appliances—Particular requirements for fans 家用和类似用途电器噪声测试方法 风扇的特殊要求 |
China National Standards Mi |
English PDF |
GB/T 4214.8-2021 |
Test method for noise of household and siMilar electrical appliances—Particular requirements for electric cooking ranges, ovens, grills, microwave ovens and any combination of these 家用和类似用途电器噪声测试方法 电灶、烤箱、烤架、微波炉及其组合器具的特殊要求 |
China National Standards Mi |
English PDF |
GB/T 3488.3-2021 |
Hardmetals—Metallographic deterMination of microstructure—Part 3: Measurement of microstructural features in Ti (C, N) and WC/cubic carbide based hardmetals 硬质合金 显微组织的金相测定 第3部分:Ti(C,N)和WC立方碳化物基硬质合金显微组织的金相测定 |
China National Standards Mi |
English PDF |
GB/T 39830-2021 |
Code for seisMic design of steel static storage systems 立体仓库钢结构货架抗震设计规范 |
China National Standards Mi |
English PDF |
GB/T 39817-2021 |
Conveyor belts—Propane burner Mid-scale flammability test method 输送带 丙烷燃烧器中规模可燃性试验方法 |
China National Standards Mi |
English PDF |
GB/T 39962-2021 |
Die casting machine -- Energy efficiency liMits and energy efficiency rating 压铸机 能效限定值及能效等级 |
China National Standards Mi |
English PDF |
GB/T 39956.2-2021 |
Pneumatic fluid power—Electro-pneumatic pressure control valves—Part 2: Test methods to deterMine main characteristics to include in the supplier's literature 气动 电-气压力控制阀 第2部分:评定商务文件中应包含的主要特性的试验方法 |
China National Standards Mi |
English PDF |
GB/T 39946-2021 |
DeterMination of prohibited Para Red in lip cosmetics -- High performance liquid chromatography 唇用化妆品中禁用物质对位红的测定 高效液相色谱法 |
China National Standards Mi |
English PDF |
GB/T 39939-2021 |
Volatile organic compounds in furniture components—Test method for the rapid deterMination in the field 家具部件中挥发性有机化合物 现场快速检测方法 |
China National Standards Mi |
English PDF |
GB/T 39935-2021 |
Plastics—Film and sheeting—DeterMination of blocking resistance 塑料制品 薄膜和片材 抗粘连性的测定 |
China National Standards Mi |
English PDF |
GB/T 39934-2021 |
Plastics—Film and sheeting—DeterMination of blocking resistance 家具中挥发性有机化合物的筛查检测方法 气相色谱-质谱法 |
China National Standards Mi |
English PDF |
GB/T 39930-2021 |
Organic light eMitting diode (OLED) panels for general lighting—Performance requirements 普通照明用有机发光二极管(OLED)面板 性能要求 |
China National Standards Mi |
English PDF |
GB/T 39927-2021 |
DeterMination of prohibited substances veratrine in cosmetics—High performance liquid chromatography 化妆品中禁用物质藜芦碱的测定 高效液相色谱法 |
China National Standards Mi |
English PDF |
GB/T 39925-2021 |
Stationary equipment for agriculture—Data communications network for livestock farMing 农业固定设备 畜牧业数据通信网络 |
China National Standards Mi |
English PDF |
GB/T 39899-2021 |
The technical specifications for remanufactured automotive components—Automatic transMission 汽车零部件再制造产品技术规范 自动变速器 |
China National Standards Mi |
English PDF |
GB/T 39897-2021 |
DeterMination of volatile organic compounds and aldehydes and ketones in nonmetallic parts of vehicles 车内非金属部件挥发性有机物和醛酮类物质检测方法 |
China National Standards Mi |
English PDF |
GB/T 39873-2021 |
DeterMination of quaternary ammonium salt in disinfectant—Liquid chromatography-tandem mass spectrometry 消毒剂中季铵盐的测定 液相色谱-串联质谱法 |
China National Standards Mi |
English PDF |
GB/T 39867-2021 |
Bismuth germanate scintillation crystal for positron eMission tomography 正电子发射断层扫描仪用锗酸铋闪烁晶体 |
China National Standards Mi |
English PDF |
GB/T 39864-2021 |
ElectrocheMical performance test of lithium manganese oxide—Test method for the initial specific discharge capacity and the initial efficiency 锰酸锂电化学性能测试 首次放电比容量及首次充放电效率测试方法 |
China National Standards Mi |
English PDF |
GB/T 39863-2021 |
AluMina ceramic substrate for copper clad laminate 覆铜板用氧化铝陶瓷基片 |
China National Standards Mi |
English PDF |
GB/T 39862-2021 |
Test method for thermal conductivity of high thermal conductivity ceraMics 高热导率陶瓷导热系数的检测 |
China National Standards Mi |
English PDF |
GB/T 39861-2021 |
ElectrocheMical performance test of lithium manganese oxide—Test method for discharge plateau capacity ratio and cycle life 锰酸锂电化学性能测试 放电平台容量比率及循环寿命测试方法 |
China National Standards Mi |
English PDF |
GB/T 39860-2021 |
Rapid identification of the surface residual Mineral powder on latex products—X-ray diffraction spectrometry 胶乳制品表面残余矿物粉末的快速鉴别 X-射线衍射法 |
China National Standards Mi |
English PDF |
GB/T 39858-2021 |
Test method for thermal conductivity of high thermal conductivity ceraMics 隧道预切槽设备 |
China National Standards Mi |
English PDF |
GB/T 39834-2021 |
Technical requirement of fully mechanized bag filling Mining with paste 综合机械化膏体袋式充填采煤技术要求 |
China National Standards Mi |
English PDF |
GB/T 39828-2021 |
Test method for deterMining elastic modulus of thick ceramic coating at elevated temperature 陶瓷厚涂层的高温弹性模量试验方法 |
China National Standards Mi |
English PDF |
GB/T 39827.2-2021 |
Plastics -- Post-consumer poly(ethylene terephthalate)(PET) bottle recyclates -- Part 2: Preparation of test specimens and deterMination properties 塑料 用过的聚对苯二甲酸乙二醇酯(PET)瓶回收物 第2部分:试样制备和性能测定 |
China National Standards Mi |
English PDF |
Find out:17024Items | To Page of: First -Previous-Next -Last | [16] [17] [18] [19] [20] [21] [22] |