Every reference with a DOI in the deposited reference list resolved to a known
work in Crossref or DataCite at the dated check, and none carried a retraction,
withdrawal, or removal notice.
The 49 references without a DOI — listed, not checked
no DOI — not checkedref1/cit1
no DOI — not checkedProceedings of the 5th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedBiasca, F. E.; Dickenson, F. E.; Chang, R. L.; Johnson, H.; Bailey, H. E.; Simbeck, D. R.Upgrading heavy crude oils and residue to transportation fuel: technology economics, and outlook, Phase 7;Garland, R., Report Coordinator; SAF Pacific Inc. Eng. & Economic Consultant, May2003.
no DOI — not checkedFurimsky, E.Catalyst for upgrading heavy petroleum feeds; Studies in Surface Science and Catalysis;Elsevier:Amsterdam,2007; p169.
no DOI — not checkedref8/cit8
no DOI — not checkedIkbal, R.; Patel, V.; Sloan, H. D.Process integration for residue upgrading. InProceedings of the 6th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands, Houston, TX, Feb.1995; Vol. 10, pp393−399
no DOI — not checkedSchulman, B. L.; Dickenson, R. L.Upgrading heavy crudes. InProceedings of the 5th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands, Caracas, Venezuela, Aug.1991; Vol. 4, pp105−113
no DOI — not checkedWashimi, K.; Ogata, Y.; Bohlman, D.Upgrading heavy oils by HSC processInProceedings of the 5th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands, Caracas, Venezuela, Aug.1991; pp115−118
no DOI — not checkedOgata, Y.; Fukuyama, H.Well-refined HSC process proves reliabilityInProceedings of the 5th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands, Caracas, Venezuela, Aug.1991, pp275−280
no DOI — not checkedref14/cit14
no DOI — not checkedref16/cit16
no DOI — not checkedCitarella, V. A.; Matula, J. P.; Puente-Duany, R. J.Commercial flexicoking experienceInProceedings of the 5th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands, Caracas, Venezuela, Aug.1991; pp119−124
no DOI — not checkedref19/cit19
no DOI — not checkedTakatsuka, T.; Watari, R.; Hayakawa, H.Catalysts in Petroleum Refining and Petrochemical Industries 1995;Absi-Halabi, M.,et al., Eds.Elsevier:Amsterdam,1996: pp223−231
no DOI — not checkedref22/cit22
no DOI — not checkedProceedings of the 3rd UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedNPRA Annual Meeting
no DOI — not checkedProceedings of the 6th UNITAR/UNDP International Conference of Heavy Crude and Tar Sands
no DOI — not checkedProceedings of the 3rd UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedref27/cit27
no DOI — not checkedProceedings of the 11th World Petroleum Congress
no DOI — not checkedProceedings of the 4th UNITAR/UNDP International Conference on Heavy Crudes and Tar Sands
no DOI — not checkedSolari, R. B.; Silva, F.; Souto, A.; De Drago, G.; Guitian, J.; Marzin, R.; Gonzales, J. C.Upgrading of bottom of barrel applying HDH technology. InProceedings of the 5th UNITAR/UNDP International Conference On Heavy Crudes and Tar sands, Caracas, Venezuela, Aug.1991; Vol. 4, pp65−74
no DOI — not checkedProceedings of the 4th UNITAR/UNDP International Conference On Heavy Crude and Tar Sands
no DOI — not checkedProceedings of the 5th UNITAR/UNDP International Conference On Heavy Crude and Tar Sands
no DOI — not checkedProceedings of the 2nd International Conference on Future of Heavy Crude and Tar Sands
no DOI — not checkedNiemann, K.Status of VCC technology-Update. InProceedings of the 5th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands, Caracas, Venezuela, Aug.1991, pp3−9
no DOI — not checkedCatalysts in Petroleum Refining
no DOI — not checkedProceedings of the 3rd UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedProceedings of the 6th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedNPRA Annual Meeting
no DOI — not checkedProceedings of the 3rd UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedProceedings of the 5th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedProceedings of the 5th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedProceedings of the 4th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedProceedings of the 5th UNITAR/UND International Conference of Heavy Crude and Tar Sands
no DOI — not checkedref48/cit48
no DOI — not checkedVan Driesen, R. P.; Fornoff, L. L.Heavy oil upgrading via hydrocracking. InProceedings of the 2nd UNITAR/UNDP International Conference on Heavy Crude and Tar Sands, Caracas, Venezuela,1982; Chapter 126, pp1195−1205
no DOI — not checkedProceedings of the 6th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedref51/cit51
no DOI — not checkedProceedings of the 7th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedProceedings of the 5th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedref55/cit55
no DOI — not checkedref58/cit58
no DOI — not checkedProceedings of the 5th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
no DOI — not checkedref60/cit60
no DOI — not checkedref61/cit61
no DOI — not checkedref62/cit62
no DOI — not checkedProceedings of the 6th UNITAR/UNDP International Conference on Heavy Crude and Tar Sands
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