If you find this page useful and would like to be notified of changes made to this page, start by inputting your email below.
powered by ChangeDetection
Well ID: 37-019-22440 | Loading map...
{"type":"SATELLITE","minzoom":false,"maxzoom":false,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"mappingservice":"googlemaps3","width":"100%","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"wmsoverlay":false,"copycoords":false,"static":false,"zoom":14,"layers":[],"controls":["pan","zoom","type","scale","streetview","rotate"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"resizable":false,"kmlrezoom":false,"poi":true,"markercluster":false,"clustergridsize":60,"clustermaxzoom":20,"clusterzoomonclick":true,"clusteraveragecenter":true,"clusterminsize":2,"imageoverlays":[],"kml":[],"gkml":[],"searchmarkers":"","enablefullscreen":false,"scrollwheelzoom":false,"locations":[{"text":"","title":"","link":"","lat":40.677247,"lon":-79.782242,"icon":""}]} |
Country: United States | |
State: Pennsylvania | |
County: Butler | |
Municipality: Buffalo Township | |
Operator Name: RANGE RESOURCES APPALACHIA LLC | |
Well Pad ID: 152550 | |
Farm/Lease Name: THOMPSON DONALD 11750 7H | |
License Status: Active | |
Spud Date: 2016-09-29 | |
Permit Date: 2015-06-15 | |
Well Type: GAS | |
Unconventional Well: Y | |
Configuration: Horizontal Well | |
Conservation: No | |
Latitude: 40.677247 | |
Longitude: -79.782242 |
Date | Event |
---|---|
2015-06-15 | New Permit Application |
2015-09-29 | Performed Spud Operation |
2015-11-03 | New Permit Application |
2016-02-16 | Drilling Completion |
2016-04-29 | Perforation |
2016-05-05 | Perforation |
2016-05-05 | Performed Stage 1 of Stimulation |
2016-05-05 | Performed Stage 2 of Stimulation |
2016-05-06 | Perforation |
2016-05-06 | Performed Stage 3 of Stimulation |
2016-05-06 | Performed Stage 4 of Stimulation |
2016-05-06 | Performed Stage 5 of Stimulation |
2016-05-07 | Perforation |
2016-05-07 | Performed Stage 6 of Stimulation |
2016-05-07 | Performed Stage 7 of Stimulation |
2016-05-07 | Performed Stage 8 of Stimulation |
2016-05-07 | Performed Stage 9 of Stimulation |
2016-05-08 | Perforation |
2016-05-08 | Performed Stage 10 of Stimulation |
2016-05-08 | Performed Stage 11 of Stimulation |
2016-05-08 | Performed Stage 12 of Stimulation |
2016-05-08 | Performed Stage 13 of Stimulation |
2016-05-08 | Performed Stage 14 of Stimulation |
2016-05-09 | Perforation |
2016-05-09 | Performed Stage 15 of Stimulation |
2016-05-09 | Performed Stage 16 of Stimulation |
2016-05-09 | Performed Stage 17 of Stimulation |
2016-05-09 | Performed Stage 18 of Stimulation |
2016-05-10 | Perforation |
2016-05-10 | Performed Stage 19 of Stimulation |
2016-05-10 | Performed Stage 20 of Stimulation |
2016-05-10 | Performed Stage 21 of Stimulation |
2016-05-10 | Performed Stage 22 of Stimulation |
2016-05-10 | Performed Stage 23 of Stimulation |
2016-05-11 | Perforation |
2016-05-11 | Performed Stage 24 of Stimulation |
2016-05-11 | Performed Stage 25 of Stimulation |
2016-12-19 | Deviated |
For data sources see[4]
Job Number | Job Start Date | Job End Date | True Vertical Depth (ft) | Total Water Volume (gal) | Total Non-Water Volume (gal) |
---|---|---|---|---|---|
1 | 2016-05-05 | 2016-05-11 | 6,648 | 5,157,860 | 0 |
Job Number | Trade Name | Supplier | Purpose | Ingredient Name | CAS Number | Additive Percentage by Mass | Job Percentage by Mass | Mass Used (lb) |
---|---|---|---|---|---|---|---|---|
1 | Sand (Proppant), DAP-925, DWP-642, Hydrochloric Acid | CWS | Propping Agent, Acid Corrosion Inhibitor, Friction Reducer, Clean Perforations | Alcohols, C12-16, ethoxylated | 68551-12-2 | 4 | 0.0021531 | 1046.3 |
Fatty acids, tall-oil | 61790-12-3 | 30 | 0.000119617 | 56.46 | ||||
Alkenes, C>10 a- | 64743-02-8 | 5 | 0.00001994 | 9.41 | ||||
Crystalline silica (Quartz) | 14808-60-7 | 100 | 10.3308 | 5,031,630.0 | ||||
Formaldehyde | 50-00-0 | 0.1 | 0.00000997 | 0.19 | ||||
Acrylamide | 79-06-1 | 0.1 | 0.00004984 | 26.16 | ||||
Modified thiourea polymer | 68527-49-1 | 30 | 0.000119617 | 56.46 | ||||
Ilmenite | 98072-94-7 | 0.1 | 0.00684806 | 3336.65 | ||||
Apatite | 64476-38-6 | 0.1 | 0.00720691 | 3509.9 | ||||
Calcite | 471-34-1 | 1 | 0.00746608 | 3638.25 | ||||
Methanol | 67-56-1 | 60 | 0.000229265 | 112.93 | ||||
Surfactant | Proprietary | 3 | 0.00161483 | 784.73 | ||||
Illite | 12173-60-3 | 1 | 0.0185007 | 9008.95 | ||||
Alcohols, C12-14, ethoxylated | 68439-50-9 | 4 | 0.0021531 | 1046.3 | ||||
Propargyl Alcohol | 107-19-7 | 10 | 0.00003987 | 18.82 | ||||
Hydrochloric acid | 7647-01-0 | 37 | 0.335086 | 163207 | ||||
Goethite | 1310-14-1 | 0.1 | 0.00791464 | 3856.4 | ||||
Sorbitan monooleate | 1338-43-8 | 3 | 0.00161483 | 784.73 | ||||
Sodium chloride | 7647-14-5 | 1 | 0.00000997 | 1.88 | ||||
Alcohols, C14-15, ethoxylated | 68951-67-7 | 30 | 0.000119617 | 56.46 | ||||
Biotite | 1302-27-8 | 0.1 | 0.00720691 | 3509.9 | ||||
2-Propenoic acid, ammonium salt, polymer with 2-propenamide, Sodium salt |
910644-97-2 | 30 | 0.0161084 | 7847.25 | ||||
Alcohols, C10-16, ethoxylated | 68002-97-1 | 4 | 0.0021531 | 1046.3 | ||||
Ethoxylated oleyl amine | 26635-93-8 | 3 | 0.00161483 | 784.73 | ||||
Ammonium acetate | 631-61-8 | 6 | 0.00321968 | 1569.45 | ||||
Paraffinic hydrocarbon solvent | 64742-47-8 | 30 | 0.0161084 | 7847.25 | ||||
MC MX 5-3886, MC MX 588-2, MC MX 8-2544 | MultiChem | Live Culture - Nitrate Reducing Bacteria, Scale Inhibitor | Water | 7732-18-5 | 100 | 0.0898642 | 43768.6 | |
Calcium Nitrate.4H2O | 13477-34-4 | 100 | 0.128596 | 62632.9 | ||||
Sodium Lactate Syrup 60% Sodium Salt | 72-17-3 | 0.1 | 0.00000938 | 4.57 | ||||
Neutralized Polycarboxylic Acid | Proprietary | 10 | 0.000740105 | 360.47 | ||||
Sodium Chloride | 7647-14-5 | 10 | 0.000937619 | 456.67 | ||||
Monopotassium Phosphate | 7778-77-0 | 0.1 | 0.00000938 | 4.57 | ||||
Non-hazardous Solvent Package | Proprietary | 50 | 0.0037005 | 1802.34 | ||||
Sodium Acetate CP Anhydrous | 127-09-3 | 0.5 | 0.00004687 | 22.83 | ||||
Yeast Extract | 8013-01-2 | 0.5 | 0.00004687 | 22.83 | ||||
Water | Customer & CWS | Base Fluid & Mix Water | Water | 7732-18-5 | 100 | 88.9122 | 43,304,900.0 |
For data sources see[5]
Stimulation Date | Phase Number | Chemical Agent | Volume (gal) | Treating Pressure (psi) | Breakdown Pressure (psi) |
---|---|---|---|---|---|
2016-05-05 | 1 | OTTOWA SAND | 52,273 | 7,267 | 6,650 |
2016-05-05 | 2 | OTTOWA SAND | 52,273 | 6,138 | 8,268 |
2016-05-06 | 3 | OTTOWA SAND | 52,273 | 6,896 | 5,738 |
2016-05-06 | 4 | OTTOWA SAND | 52,273 | 6,974 | 5,686 |
2016-05-06 | 5 | OTTOWA SAND | 52,273 | 6,891 | 6,206 |
2016-05-07 | 6 | OTTOWA SAND | 52,273 | 6,957 | 5,433 |
2016-05-07 | 7 | OTTOWA SAND | 52,273 | 6,878 | 7,921 |
2016-05-07 | 8 | OTTOWA SAND | 52,273 | 6,760 | 6,417 |
2016-05-07 | 9 | OTTOWA SAND | 52,273 | 6,813 | 6,191 |
2016-05-08 | 10 | OTTOWA SAND | 52,273 | 6,795 | 8,058 |
2016-05-08 | 11 | OTTOWA SAND | 52,273 | 6,477 | 6,452 |
2016-05-08 | 12 | OTTOWA SAND | 52,273 | 6,808 | 5,530 |
2016-05-08 | 13 | OTTOWA SAND | 52,273 | 7,029 | 6,788 |
2016-05-08 | 14 | OTTOWA SAND | 52,273 | 6,953 | 6,065 |
2016-05-09 | 15 | OTTOWA SAND | 52,273 | 6,701 | 5,356 |
2016-05-09 | 16 | OTTOWA SAND | 52,273 | 7,104 | 9,095 |
2016-05-09 | 17 | OTTOWA SAND | 52,273 | 6,852 | 7,127 |
2016-05-09 | 18 | OTTOWA SAND | 52,273 | 6,554 | 5,523 |
2016-05-10 | 19 | OTTOWA SAND | 52,273 | 6,458 | 7,079 |
2016-05-10 | 20 | OTTOWA SAND | 52,273 | 6,473 | 6,069 |
2016-05-10 | 21 | OTTOWA SAND | 52,273 | 6,710 | 5,478 |
2016-05-10 | 22 | OTTOWA SAND | 52,273 | 6,819 | 5,773 |
2016-05-10 | 23 | OTTOWA SAND | 52,273 | 6,759 | 5,740 |
2016-05-11 | 24 | OTTOWA SAND | 52,273 | 6,298 | 6,271 |
2016-05-11 | 25 | OTTOWA SAND | 52,273 | 5,935 | 5,060 |
For data sources see[6]
Period | Operator Name | Gas Quantity (mcf) | Gas Production Days | Oil Quantity (bbl) | Oil Production Days | Water Quantity (bbl) | Water Production Days |
---|---|---|---|---|---|---|---|
2015 | RANGE RESOURCES APPALACHIA LLC | 0.00 | 0 | 0.00 | 0 | 0.00 | 0 |
2016 | RANGE RESOURCES APPALACHIA LLC | 886,604.87 | 204 | 0.00 | 0 | 0.00 | 0 |
2017 | RANGE RESOURCES APPALACHIA LLC | 949,869.62 | 365 | 0.00 | 0 | 0.00 | 0 |
2018 | RANGE RESOURCES APPALACHIA LLC | 686,231.17 | 344 | 0.00 | 0 | 0.00 | 0 |
2019 | RANGE RESOURCES APPALACHIA LLC | 554,398.81 | 360 | 0.00 | 0 | 0.00 | 0 |
For data sources see[7]
Period | Operator | Waste Type | Quantity | Disposal Method | Waste Facility ID |
---|---|---|---|---|---|
2015 | RANGE RESOURCES APPALACHIA LLC | Drilling Fluid Waste | 95.24 Bbl | REUSE OTHER THAN ROAD SPREADING | |
2015 | RANGE RESOURCES APPALACHIA LLC | Drill Cuttings | 12.19 Tons | LANDFILL | 100585 |
2015 | RANGE RESOURCES APPALACHIA LLC | Drilling Fluid Waste | 1,328.10 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2015 | RANGE RESOURCES APPALACHIA LLC | Drill Cuttings | 460.86 Tons | LANDFILL | CID # 28726 |
2015 | RANGE RESOURCES APPALACHIA LLC | Drilling Fluid Waste | 1,328.10 Bbl | CENT WASTE TRT FAC NPDES | PA0254185 |
2016 | RANGE RESOURCES APPALACHIA LLC | Fracturing Fluid Waste | 67.12 Tons | RESIDUAL WASTE TRANSFER FACILITY | 101532 |
2016 | RANGE RESOURCES APPALACHIA LLC | Drilling Fluid Waste | 1,061.29 Bbl | REUSE OTHER THAN ROAD SPREADING | |
2016 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 657.38 Bbl | REUSE OTHER THAN ROAD SPREADING | |
2016 | RANGE RESOURCES APPALACHIA LLC | Synthetic Liner Materials | 11.32 Tons | LANDFILL | 100172 |
2016 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 650.21 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW019 |
2016 | RANGE RESOURCES APPALACHIA LLC | Drilling Fluid Waste | 8.37 Bbl | LANDFILL | 100172 |
2016 | RANGE RESOURCES APPALACHIA LLC | Fracturing Fluid Waste | 10,266.57 Bbl | REUSE OTHER THAN ROAD SPREADING | |
2016 | RANGE RESOURCES APPALACHIA LLC | Drilling Fluid Waste | 1,413.33 Bbl | RESIDUAL WASTE TRANSFER FACILITY | 101532 |
2016 | RANGE RESOURCES APPALACHIA LLC | Drilling Fluid Waste | 726.55 Bbl | CENT WASTE TRT FAC NPDES | PA0254185 |
2016 | RANGE RESOURCES APPALACHIA LLC | Filter Socks | 0.08 Tons | RESIDUAL WASTE TRANSFER FACILITY | 101532 |
2016 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 340.00 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW019 |
2016 | RANGE RESOURCES APPALACHIA LLC | Fracturing Fluid Waste | 405.00 Bbl | CENT WASTE TRT FAC NPDES | PA0254185 |
2016 | RANGE RESOURCES APPALACHIA LLC | Synthetic Liner Materials | 2.94 Tons | RESIDUAL WASTE TRANSFER FACILITY | 101532 |
2016 | RANGE RESOURCES APPALACHIA LLC | Drilling Fluid Waste | 835.52 Bbl | CENTRALIZED TREATMENT PLANT FOR RECYCLE | WMGR123SW019 |
2016 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 151.75 Bbl | CENT WASTE TRT FAC NPDES | PA0254185 |
2016 | RANGE RESOURCES APPALACHIA LLC | Fracturing Fluid Waste | 225.71 Bbl | CENTRALIZED TREATMENT PLANT FOR RECYCLE | WMGR123SW019 |
2016 | RANGE RESOURCES APPALACHIA LLC | Fracturing Fluid Waste | 610.71 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW019 |
2016 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 650.21 Bbl | CENTRALIZED TREATMENT PLANT FOR RECYCLE | WMGR123SW019 |
2016 | RANGE RESOURCES APPALACHIA LLC | Fracturing Fluid Waste | 860.00 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2016 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 151.75 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2016 | RANGE RESOURCES APPALACHIA LLC | Drilling Fluid Waste | 835.52 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW019 |
2016 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 1,995.00 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2016 | RANGE RESOURCES APPALACHIA LLC | Drilling Fluid Waste | 726.55 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2016 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 3,915.00 Bbl | REUSE OTHER THAN ROAD SPREADING | |
2016 | RANGE RESOURCES APPALACHIA LLC | Drill Cuttings | 154.34 Tons | LANDFILL | 100620 |
2016 | RANGE RESOURCES APPALACHIA LLC | Drill Cuttings | 45.38 Tons | LANDFILL | 100172 |
2017 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 212.52 Bbl | REUSE (AT WELL PAD) | |
2017 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 103.73 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW019 |
2017 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 4.17 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2017 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 334.80 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2017 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 367.92 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW019 |
2017 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 1,138.37 Bbl | REUSE (AT WELL PAD) | |
2018 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 1,656.55 Bbl | REUSE (AT WELL PAD) | |
2018 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 207.60 Bbl | REUSE (AT WELL PAD) | |
2018 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 2.00 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW030 |
2018 | RANGE RESOURCES APPALACHIA LLC | Synthetic Liner Materials | 1.22 Tons | LANDFILL | CID # 28726 |
2018 | RANGE RESOURCES APPALACHIA LLC | Soil Contaminated by Oil | 0.03 Tons | RESIDUAL WASTE TRANSFER FACILITY | 101532 |
2018 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 212.47 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW030 |
2018 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 71.65 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW019 |
2018 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 69.68 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2018 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 580.49 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW019 |
2018 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 2,146.03 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2018 | RANGE RESOURCES APPALACHIA LLC | Soil Contaminated by Oil & Gas Related Spills | 0.03 Tons | RESIDUAL WASTE TRANSFER FACILITY | 101532 |
2019 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 27.58 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2019 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 248.93 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW015 |
2019 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 229.64 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW005 |
2019 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 11.87 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW015 |
2019 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 106.51 Bbl | RESIDUAL WASTE PROCESSING FACILITY | WMGR123SW019 |
2019 | RANGE RESOURCES APPALACHIA LLC | Other Oil & Gas Wastes | 61.30 Bbl | REUSE (AT WELL PAD) | |
2019 | RANGE RESOURCES APPALACHIA LLC | Produced Fluid | 1,272.31 Bbl | REUSE (AT WELL PAD) |
For data sources see[8]
Inspection ID | Inspection Category | Inspection Date | Inspection Type | Inspection Result | Inspection Comments |
---|---|---|---|---|---|
2412342 | Primary Facility | 2015-10-01 | Drilling/Alteration | No Violations Noted | |
2420799 | Primary Facility | 2015-10-27 | Drilling/Alteration | No Violations Noted | |
2450421 | Primary Facility | 2016-02-18 | Routine/Partial Inspection | No Violations Noted | |
2481937 | Primary Facility | 2016-05-04 | Routine/Partial Inspection | No Violations Noted | |
2535896 | Primary Facility | 2016-11-14 | Administrative/File Review | No Violations Noted | |
2585966 | Primary Facility | 2017-04-17 | Routine/Partial Inspection | No Violations Noted | |
2636604 | Primary Facility | 2017-09-13 | Routine/Partial Inspection | No Violations Noted | At the time of inspection, well is producing. Well integrity appears to be in good condition, with no signs of any leaks or spills at the site. Cellar was filled with gravel. A surge tank is being used on the on the plumbing for the surface casing annulus. The gauge for tubing pressure was reading 1100 psi. Well was properly labeled and Emergency Response sign remains posted at the lease entrance. There are 2 line heaters onsite. There are also 2 tanks for produced water contained within a lined, steel dike. Wells on location make dry gas. |
2760448 | Primary Facility | 2018-08-02 | Routine/Partial Inspection | No Violations Noted | On 8/02/2018, WQS Brian MacQuarrie onsite. Five wells drilled and in production 1H-019-22598, 3H-019-22599, 2H-019-22457, 6H-019-22458 and 7H-019-22440. Two 500 bbl tanks installed within containment. Erosion and Sedimentation BMPs maintained. Vegetation well established in previously disturbed areas. |
2777256 | Primary Facility | 2018-09-19 | Routine/Partial Inspection | No Violations Noted | On 9/19/2018, WQS Brian MacQuarrie onsite. Five wells in production. The 1H-019-22598, 2H-019-22457, 3H-019-22599, 6H-019-22458 and 7H-019-22440. Tank battery consists of two 500 bbl tanks installed within containment. Infiltration basin recently installed. Check Erosion and Sedimentation plan for redlines which included addition of compost filter sock and cross culvert installation under access road. |
2816178 | Primary Facility | 2018-12-17 | Routine/Partial Inspection | No Violations Noted | On 12/17/2018, WQS Brian MacQuarrie onsite. Five wells drilled and in production, 1H (019-22598), 2H (019-22457), 3H (019-22599), 6H (019-22458) and 7H (019-22440). Production equipment consists of two 500 bbl tanks in containment and five GPUs. Erosion and Sedimentation BMPs installed and maintained. Site well vegetated in previously disturbed areas. |
For data sources see[9]