- Alternative technologies for oil shale liquefaction and upgradingLuik, HansInternational Oil Shale Symposium : Tallinn, Estonia, June 8-11, 2009 : future energy solutions : come and share your vision!2009 / p. 44-45 http://www.ester.ee/record=b4775098*est
- Applicability of static supercritical carbon dioxide extraction in biogeochemical characterization of oil shalesLuik, Hans; Luik, Lea; Palu, Vilja; Šarajeva, Galina; Gregor, AndreAmerican journal of analytical chemistry2014 / p. 173-180 : ill
- Catalytic hydrogenation of thermobitumenKrasulina, Julia; Bitjukov, Mihhail; Vink, Natalia; Gregor, Andre; Luik, Lea; Luik, HansInternational oil shale symposium : Tallinn, Estonia, June 10-13, 20132013 / p. 56-57
- Catalytic thermal liquefaction of oil shale in tetralinJohannes, Ille; Tiikma, Laine; Luik, Hans; Tamvelius, Hindrek; Krasulina, JuliaISRN Chemical Engineering2012 / Article ID 617363, [11] p. https://www.hindawi.com/journals/isrn/2012/617363/
- Cleaner liquefaction of oil shale - is it feasible?Luik, Hans; Luik, LeaInternational Symposium "Oil shale 100 years" : Estonia, Sept. 20-23, 2016 : [abstracts]2016 / p. 41-42
- Co-conversion of Salix biomass and oil shale in the medium of supercritical waterLuik, Hans; Palu, Vilja; Tamvelius, Hindrek; Luik, Lea; Sokolova, Julia16th European Biomass Conference & Exhibition : from Research to Industry and Markets : proceedings of the International Conference held in Valencia, Spain, 2-6 June 20082008 / p. 2007-2009
- Comparative hydroliquefaction of pine Pinus sylvesteris wood and bark [Electronic resource]Luik, Hans; Luik, Lea; Vink, Natalia; Kozõreva, Jekaterina; Sokolova, Julia15th European Biomass Conference & Exhibition : from Research to Market Deployment : Florence, Italy2007 / p. 1951-1954 [CD-ROM] https://www.etis.ee/Portal/Publications/Display/4b3b9aa0-26f4-4ddd-81f7-6d0e5095e579
- Comparative thermochemical conversion processing of biomass and fossil fuel [Electronic resource]Luik, Hans; Luik, Lea; Veski, Rein14th European Biomass Conference : proceedings2006 / p. 727-730 [CD-ROM]
- Conversion of pine Pinus sylvestris cones with supercritical waterLuik, Lea; Luik, Hans; Tamvelius, Hindrek; Palu, Vilja; Kruusement, Kristjan17th European Biomass Conference & Exhibition from Research to Industry and Markets : proceedings of the International Conference held in Hamburg, Germany, 29 June - 3 July 20092009 / p. 1941-1944
- Conversion of the Estonian fossil and renewable feedstocks in the medium of supercritical waterLuik, Lea; Luik, Hans; Palu, Vilja; Kruusement, Kristjan; Tamvelius, HindrekAdvances in Analytical and Applied Pyrolysis 2006-2008 : book of abstracts of the communications presented to the 18th International Symposium on Analytical and Applied Pyrolysis : Lanzarote, Canary Islands, May 18-23, 20082008 / p. 247 https://www.sciencedirect.com/science/article/pii/S0165237008001253
- Conversion of the Estonian fossil and renewable feedstocks in the medium of supercritical waterLuik, Lea; Luik, Hans; Palu, Vilja; Kruusement, Kristjan; Tamvelius, HindrekJournal of analytical and applied pyrolysis2009 / 1/2, p. 492-496 : ill https://www.sciencedirect.com/science/article/pii/S0165237008001253
- Conversion of willow biomass at varied thermochemical conditions [Electronic resource]Luik, Hans; Luik, Lea; Tamvelius, Hindrek14th European Biomass Conference : proceedings2006 / p. 940-942 [CD-ROM]
- Co-processing of biomass and heavy shale oil using catalytical hydrocracking methodLuik, Hans; Luik, Lea; Johannes, Ille; Tiikma, Laine; Sokolova, Julia17th European Biomass Conference & Exhibition from Research to Industry and Markets : proceedings of the International Conference held in Hamburg, Germany, 29 June - 3 July 20092009 / p. 1082-1084
- Co-processing of oil shale with some other energy sourcesLuik, Hans; Bojesen-Koefoed, Jorgen; Luik, Lea; Palu, Vilja; Sokolova, Julia; Tamvelius, Hindrek; Tiikma, LaineInternational Oil Shale Symposium : Tallinn, Estonia, June 8-11, 2009 : future energy solutions : come and share your vision!2009 / p. 71-72 http://www.ester.ee/record=b4775098*est
- Copyrolysis of Estonian oil shale and peatSokolova, Julia; Luik, Hans; Palu, ViljaInternational Oil Shale Symposium : Tallinn, Estonia, June 8-11, 2009 : future energy solutions : come and share your vision!2009 / p. 75 http://www.ester.ee/record=b4775098*est
- Dealkylation kinetics of alkylresorcinols by shock heating pyrolysisLuik, Hans; Tiikma, Laine; Johannes, Ille; Kruusement, Kristjan20th International Symposium on Analytical and Applied Pyrolysis : PYRO 2014 : 19-23 May 2014, Birmingham, UK : conference guide and abstracts2014 / p. 79
- Determination of the changes in the fractional composition of kukersite retorting oil occuring at varied conditions of thermal modificationLuik, Hans; Maripuu, Lea; Vink, Natalia23rd Estonian Chemistry Days : abstracts of scientific conference1997 / p. 82
- Diktüoneemakilda ekstraktsioon superkriitilise fluiidigaKruusement, Kristjan; Palu, Vilja; Šarajeva, Galina; Luik, HansXXXIII Eesti Keemiapäevad : teaduskonverentsi teesid2013 / lk. 38
- Diktüoneemakilda termokeemiline destruktsioonLuik, HansArutame diktüoneema-argilliidist : foorum : Tallinn, 6. november, 20142014 / [14] lk
- Eesti põlevkivi hüdrogenisatsioon ja vääristatud õli omadusiLuik, Hans; Vink, Natalia; Lindaru, E.XVI Eesti keemiapäevad : teaduskonverentsi ettekannete referaadid = 16th Estonian chemistry days : abstracts of scientific conference1995 / lk. 73-74
- Effect of different temperature-time combinations in kerogen pyrolysis to thermobitumen and oilŠarajeva, Galina; Luik, Lea; Luik, HansInternational journal of environmental engineering2015 / p. 174-181 : ill http://seekdl.org/nm.php?id=5785
- Effect of different temperature-time combinations in kerogen pyrolysis to thermobitumen and oilLuik, Lea; Luik, Hans; Šarajeva, Galina20th International Symposium on Analytical and Applied Pyrolysis : PYRO 2014 : 19-23 May 2014, Birmingham, UK : conference guide and abstracts2014 / p. 80
- Effect of different temperature-time combinations in kerogen pyrolysis to thermobitumen and oilŠarajeva, Galina; Luik, Lea; Luik, Hans2014 proceedings of Second International Conference On Advances in Applied Science and Environmental Engineering : 20-21 December, 2014, Kuala Lumpur, Malaysia2014 / p. 40-47 : ill
- Effect of organic matter content and type of mineral matter on the oil yield from oil shalesJohannes, Ille; Luik, Hans; Bojesen-Koefoed, Jorgen; Tiikma, Laine; Vink, Natalia; Luik, LeaOil shale2012 / p. 206-221 : ill https://www.researchgate.net/publication/274439293_Effect_of_organic_matter_content_and_type_of_mineral_matter_on_the_oil_yield_from_oil_shales
- Extraction of kukersite shale in aqueous mixturesLuik, Hans; Maripuu, Lea; Vink, Natalia; Lindaru, E.24th Estonian Chemistry Days : abstracts of scientific conference1998 / p. 41
- Extraction of oil from Jordanian Attarat oil shaleTiikma, Laine; Johannes, Ille; Luik, Hans; Lepp, Ardi; Šarajeva, GalinaOil shale2015 / p. 218-239 : ill http://dx.doi.org/10.3176/oil.2015.3.03 https://artiklid.elnet.ee/record=b2740510*est
- Fast pyrolysis of Estonian oil shaleArpiainen, Vesa; Luik, Hans; Luik, Lea; Oasmaa, Anja; Solantausta, YrjöInternational Oil Shale Symposium : Tallinn, Estonia, June 8-11, 2009 : future energy solutions : come and share your vision!2009 / p. 29-30 http://www.ester.ee/record=b4775098*est
- Fixation of chlorine evolved in pyrolysis of PVC waste by Estonian oil shalesTiikma, Laine; Johannes, Ille; Luik, HansJournal of analytical and applied pyrolysis2006 / 2, p. 205-210 : ill
- Fundamentals to the maximum upgrading of oil shaleLuik, Hans; Luik, Lea; Šarajeva, Galina; Krasulina, Julia; Johannes, Ille; Kruusement, KristjanAbstracts book of 34th Oil Shale Symposium : October 13-17, 2014, Colorado School of Mines, Golden, Colorado2014 / p. 45
- Gasification and liquefaction of solid fuels by hydrothermal conversion methodsKruusement, Kristjan; Luik, Hans; Waldner, Maurice; Vogel, Frederic; Luik, LeaJournal of analytical and applied pyrolysis2014 / p. 265-273 : ill
- Kukersiidi termolüüsil moodustuvate asfalteenide lagunemise mõningatest seaduspärasustest = Some regularities of the decomposition of asphaltenes formed on kukersite shale thermolysisLuik, Hans; Maripuu, Lea; Vink, Natalia; Lindaru, E.XVII Eesti keemiapäevad : teaduskonverentsi ettekannete referaadid = 17th Estonian Chemistry Days : abstracts of scientific conference1996 / lk. 105-106 https://www.ester.ee/record=b1070511*est
- Kukersiidi utteõli termilise modifitseerimisdiapasooni piiritlemine õli restruktureerimisparameetritega keemispiiri muutuse aluselLuik, Hans; Maripuu, Lea; Vink, NataliaXXIII Eesti keemiapäevad : teaduskonverentsi ettekannete referaadid1997 / lk. 73
- Liquefaction and gasification of Estonian oil shales in the medium of hot compressed waterKruusement, Kristjan; Luik, Hans; Luik, Lea; Palu, Vilja; Vink, Natalia; Vogel, FredericInternational Oil Shale Symposium : Tallinn, Estonia, June 8-11, 2009 : future energy solutions : come and share your vision!2009 / p. 42-43 http://www.ester.ee/record=b4775098*est
- Liquefaction of Estonian kukersite oil shale kerogen with selected superheated solvents in static conditionsLuik, Hans; Palu, Vilja; Bitjukov, Mihhail; Luik, Lea; Kruusement, Kristjan; Tamvelius, Hindrek; Pryadka, N.Oil shale2005 / 1, p. 25-36 : ill https://artiklid.elnet.ee/record=b2342140*est
- Low temperature pyrolysis of graptolite argillite (Dictyonema shale) in autoclavesŠarajeva, Galina; Tiikma, Laine; Luik, Hans; Johannes, IlleInternational journal of engineering research and applications2015 / p. 16-22 : ill http://www.ijera.com/papers/Vol5_issue11/Part%20-%201/D511011622.pdf
- Low-temperature pyrolysis and co-pyrolysis of Göynük oil shale and terebinth berries (Turkey) in an autoclaveYanik, J.; Secim, P.; Karakaya, S.; Tiikma, Laine; Luik, Hans; Krasulina, Julia; Raik, Peep; Palu, ViljaOil shale2011 / p. 469-486 : ill https://artiklid.elnet.ee/record=b2463385*est
- Mathematic models for kinetics of batchwise hydrogenation of shale oilJohannes, Ille; Luik, Hans; Kruusement, KristjanFuel processing technology2006 / 8, p. 711-716 : ill
- Parallels between slow pyrolysis of Estonian oil shale and forest biomass residuesLuik, Hans; Luik, Lea; Tiikma, Laine; Vink, NataliaJournal of analytical and applied pyrolysis2007 / 1/2, p. 205-209
- Parallels between slow pyrolysis of Estonian oil shale and forest biomass residuesLuik, Hans; Luik, Lea; Tiikma, Laine; Vink, Natalia17th International Symposium on Analytical and Applied Pyrolysis : Budapest, Hungary, May 21-26, 2006 : book of abstracts2006 / p. 158
- Peat semicoking and hydrocrackingLuik, Hans; Palu, Vilja; Luik, Lea; Sokolova, Julia; Bojesen-Koefoed, JorgenJournal of analytical and applied pyrolysis2009 / 1/2, p. 497-501 : ill https://www.sciencedirect.com/science/article/abs/pii/S0165237008001241
- Peat semicoking and hydrocrackingLuik, Hans; Palu, Vilja; Luik, Lea; Sokolova, JuliaAdvances in Analytical and Applied Pyrolysis 2006-2008 : book of abstracts of the communications presented to the 18th International Symposium on Analytical and Applied Pyrolysis : Lanzarote, Canary Islands, May 18-23, 20082008 / p. 248 https://www.sciencedirect.com/science/article/pii/S0165237008001241
- Puukoor kui võimalik keemiatööstuse toore vedelkütuste ja kemikaalide saamiseksVeski, Rein; Palu, Vilja; Joa, Kelly; Kruusement, Kristjan; Luik, HansTaastuvate energiaallikate uurimine ja kasutamine : kuuenda konverentsi kogumik : [11. nov. 2004, Tartu]2005 / lk. 119-131 : ill
- Põlevkivi: mitte pelgalt põlev kivi, vaid Eesti naftaLuik, HansÄripäev2006 / 9. mai, lk. 23 https://www.aripaev.ee/uudised/2006/05/08/polevkivi-mitte-pelgalt-polev-kivi-vaid-eesti-nafta
- Pyrolysis and supercritical water conversion of pine Pinus sylvestris ingredientsLuik, Hans; Luik, Lea; Palu, Vilja; Tamvelius, Hindrek21st European Biomass Conference and Exhibition2013 / p. 914-917
- Rapid characterisation and investigation of oil shales by thermal desorption-pyrolysis-GC/MS using multi-functional pyrolyzerWatanabe, Chuichi; Luik, Hans; Yuzawa, TetsuroInternational Oil Shale Symposium : Tallinn, Estonia, June 8-11, 2009 : future energy solutions : come and share your vision!2009 / p. 59-60 http://www.ester.ee/record=b4775098*est
- Stepwise supercritical carbon dioxide extraction of Estonian oil shales in batch autoclave in temperature region 40-150 °CLuik, Hans; Palu, Vilja; Luik, Lea; Šarajeva, GalinaOrganic Geochemistry : Trends for the 21st Century : book of abstracts of the communications presented to the 26th International Meeting on Organic Geochemistry, Costa Adeje, Tenerife - Spain, September 15-20, 2013. Vol. 22013 / p. 205-206
- Study of the organic liquid obtained from supercritical water conversion of Estonian dictyonema and kukersite oil shale by PY-GC/MSChiavari, Giuseppe; Fabbri, Daniele; Finessi, Emanuela; Luik, Hans; Luik, Lea; Montalbani, Simona; Prati, SilvaInternational Oil Shale Symposium : Tallinn, Estonia, June 8-11, 2009 : future energy solutions : come and share your vision!2009 / p. 67 http://www.ester.ee/record=b4775098*est
- Supercritical extraction of the Estonian kukersite oil shaleLuik, HansAdvances in energy research. Volume 22011 / p. 283-298
- Supercritical fluid extraction of dictyonema oil shaleKruusement, Kristjan; Palu, Vilja; Šarajeva, Galina; Luik, HansInternational oil shale symposium : Tallinn, Estonia, June 10-13, 20132013 / p. 67
- Synergy in co-liquefaction of oil shale and willow in supercritical waterJohannes, Ille; Luik, Hans; Palu, Vilja; Kruusement, Kristjan; Gregor, AndreFuel2015 / p. 180-187 : ill http://dx.doi.org/10.1016/j.fuel.2014.12.031
- Synergy in co-pyrolysis of oil shale and pine sawdust in autoclavesJohannes, Ille; Tiikma, Laine; Luik, HansJournal of analytical and applied pyrolysis2013 / 341-352 : ill
- Synergy in hydrous pyrolysis of oil shale and sawdust blendsJohannes, Ille; Tiikma, Laine; Luik, Hans; Gregor, Andre20th International Symposium on Analytical and Applied Pyrolysis : PYRO 2014 : 19-23 May 2014, Birmingham, UK : conference guide and abstracts2014 / p. 70
- Synergy in the hydrothermal pyrolysis of oil shale/sawdust blendsTiikma, Laine; Johannes, Ille; Luik, Hans; Gregor, AndreJournal of Analytical and Applied Pyrolysis2016 / p. 247 - 256 https://doi.org/10.1016/j.jaap.2015.11.008 Journal metrics at Scopus Article at Scopus Journal metrics at WOS Article at WOS
- Termobituumeni katalüütiline hüdrogeenimineKrasulina, Julia; Bitjukov, Mihhail; Vink, Natalia; Gregor, Andre; Luik, Lea; Luik, HansXXXIII Eesti Keemiapäevad : teaduskonverentsi teesid2013 / lk. 35
- Termochemical co-liquefaction of biomass wastes and Estonian oil shale [Electronic resource]Luik, Lea; Luik, Hans; Bitjukov, Mihhail; Kruusement, Kristjan; Sokolova, Julia; Tamvelius, HindrekSuccess & visions for bioenergy. Thermal processing of biomass for bioenergy, biofuels and bioproducts2007 / [8] p. [CD-ROM]
- The possibility of extracting oil shale organic matter during the bitumen generation stageFomitšov, Mihhail; Luik, HansAbstracts book of 34th Oil Shale Symposium : October 13-17, 2014, Colorado School of Mines, Golden, Colorado2014 / p. 54-55
- Thermal dissolution of Estonian oil shaleTiikma, Laine; Johannes, Ille; Luik, Hans; Zaidentsal, Aleksei; Vink, NataliaAdvances in Analytical and Applied Pyrolysis 2006-2008 : book of abstracts of the communications presented to the 18th International Symposium on Analytical and Applied Pyrolysis : Lanzarote, Canary Islands, May 18-23, 20082008 / p. 265
- Thermal dissolution of Estonian oil shaleTiikma, Laine; Johannes, Ille; Luik, Hans; Zaidentsal, Aleksei; Vink, NataliaJournal of analytical and applied pyrolysis2009 / 1/2, p. 502-507 : ill
- Thermal extraction of oil from a Utah Green River (USA) oil shale in autoclavesJohannes, Ille; Tiikma, Laine; Luik, Hans; Šarajeva, GalinaInternational journal of engineering and applied sciences (EAAS)2015 / p. 23-35 : ill http://eaas-journal.org/survey/userfiles/files/v6i504%20Oil%20Shale%20and%20Renewables%20Research(1).pdf
- Thermochemical Co-liquefaction of Estonian kukersite oil shale with peat and pine barkKrasulina, Julia; Luik, Hans; Palu, Vilja; Tamvelius, HindrekOil shale2012 / p. 222-236 : ill https://artiklid.elnet.ee/record=b2527827*est
- Thermochemical co-liquefaction of woody biomass and fossil fuel in supercritical water [Electronic resource]Luik, Lea; Luik, Hans; Vink, Natalia; Kruusement, Kristjan; Veski, Rein15th European Biomass Conference & Exhibition : from Research to Market Deployment : Florence, Italy2007 / p. 1955-1959 [CD-ROM]
- Thermochemical conversion of woody biomass by using slow pyrolysis and direct hydrogenation methodsLuik, Hans; Luik, Lea; Gregor, AndreWasteEng 2014 : 5th International Conference on Engineering for Waste and Biomass Valorisation, Rio de Janeiro, Brazil, August 25-28, 2014 : proceedings2014 / p. 1532-1541
- Thermochemical conversion of woody biomass by using slow pyrolysis and direct hydrogenation methodsLuik, Hans; Luik, Lea; Gregor, AndreWasteEng 2014 : 5th International Conference on Engineering for Waste and Biomass Valorisation, Rio de Janeiro, Brazil, August 25-28, 2014 : abstracts2014 / p. 217
- Thermochemical destruction of graptolite argillite = Graptoliit-argilliidi termokeemiline destruktsioonŠarajeva, Galina2016 https://www.ester.ee/record=b4566155*est
- Thermochemical liquefaction of reedVeski, Rein; Palu, Vilja; Luik, Hans; Kruusement, KristjanProceedings of the Estonian Academy of Sciences. Chemistry2005 / 1, p. 45-56 : ill
- Thermochemical liquefaction of reed [Electronic resource]Veski, Rein; Palu, Vilja; Luik, Hans; Kruusement, Kristjan14th European Biomass Conference : proceedings2006 / p. 947-949 [CD-ROM] https://go.gale.com/ps/i.do?id=GALE%7CA198705954&sid=googleScholar&v=2.1&it=r&linkaccess=abs&issn=14060124&p=AONE&sw=w&userGroupName=anon%7Eec7ac821&aty=open-web-entry
- Transformations of biomass internal oxygen at varied pyrolysis conditionsLuik, Hans; Johannes, Ille; Palu, Vilja; Luik, Lea; Kruusement, Kristjan17th International Symposium on Analytical and Applied Pyrolysis : Budapest, Hungary, May 21-26, 2006 : book of abstracts2006 / p. 139
- Transformations of biomass internal oxygen at varied pyrolysis conditionsLuik, Hans; Johannes, Ille; Palu, Vilja; Luik, Lea; Kruusement, KristjanJournal of analytical and applied pyrolysis2007 / 1/2, p. 121-127
- Trends in biomass thermochemical liquefaction : global experience and recent studies in EstoniaLuik, Hans; Palu, Vilja; Luik, Lea; Kruusement, Kristjan; Tamvelius, Hindrek; Veski, Rein; Vetkov, Nikolai; Vink, Natalia; Bitjukov, MihhailProceedings of the Estonian Academy of Sciences. Chemistry2005 / 4, p. 194-229 : ill
- Upgrading of Estonian shale oil distillation fractions. 2, The effect of time and hydrogen pressure on the yield and composition of "diesel fraction" hydrogenation productsLuik, Hans; Vink, Natalia; Lindaru, E.; Maripuu, LeaOil shale1999 / 3, p. 249-256: ill https://artiklid.elnet.ee/record=b1001550*est
- Upgrading of Estonian shale oil distillation fractions. 3, Hydrogenation of light mazuteLuik, Hans; Vink, Natalia; Lindaru, E.; Maripuu, LeaOil shale1999 / 4, p. 331-336 https://artiklid.elnet.ee/record=b1001550*est
- Upgrading of Estonian shale oil distillation fractions. 4, The effect of time and hydrogen pressure on the yield and composition of light mazute hydrogenation productsLuik, Hans; Vink, Natalia; Lindaru, E.; Maripuu, LeaOil shale1999 / 4, p. 337-342: ill https://artiklid.elnet.ee/record=b1001550*est
- Upgrading of Estonian shale oil heavy residuum bituminous fraction by catalytic hydroconversionLuik, Hans; Luik, Lea; Johannes, Ille; Tiikma, Laine; Vink, Natalia; Palu, Vilja; Bitjukov, Mihhail; Tamvelius, Hindrek; Krasulina, Julia; Kruusement, Kristjan; Nechaev, IgorFuel processing technology2014 / p. 115-122 : ill
- Upgrading of liquid products from Estonian kukersite oil shale by catalytic hydrogenation = Kukersiitpõlevkivi vedelproduktide vääristamine katalüütilise hüdrogeenimise meetodilKrasulina, Julia2015 https://www.ester.ee/record=b4471946*est
- Upgrading shale oil heavy fractions with biomass via catalytical hydroprocessing [Electronic resource]Luik, Hans; Luik, Lea; Tiikma, Laine; Vink, Natalia; Kozõreva, JekaterinaSuccess & visions for bioenergy. Thermal processing of biomass for bioenergy, biofuels and bioproducts2007 / [7] p. [CD-ROM]
- Utilization of solid waste as an additive in shale oil productionLuik, Lea; Tiikma, Laine; Luik, Hans; Vink, Natalia; Bitjukov, MihhailWasteEng 2014 : 5th International Conference on Engineering for Waste and Biomass Valorisation, Rio de Janeiro, Brazil, August 25-28, 2014 : proceedings2014 / p. 252-259
- Utilization solid waste as an additive in shale oil productionTiikma, Laine; Luik, Lea; Luik, Hans; Vink, Natalia; Bitjukov, MihhailWasteEng 2014 : 5th International Conference on Engineering for Waste and Biomass Valorisation, Rio de Janeiro, Brazil, August 25-28, 2014 : abstracts2014 / p. 53
- Water conversion of oil shales and biomass = Põlevkivi ja biomassi vesikonversioonKruusement, Kristjan2007
- Õli peitub mujalgi kui põlevkivis : [põlevkivi ja taastuvkütuste teaduslaboratooriumi juhataja Hans Luige arvamused]Luik, Hans; Aru, ErikMente et Manu2013 / lk. 9 : fot https://artiklid.elnet.ee/record=b2601395*est