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Author |
Fernandez, A.; Hufschmidt, D.; Colaux, J.L.; Valiente-Dobon, J.J.; Godinho, V.; Jimenez de Haro, M.C.; Feria, D.; Gadea, A.; Lucas, S. |
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Title |
Low gas consumption fabrication of He-3 solid targets for nuclear reactions |
Type |
Journal Article |
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Year |
2020 |
Publication |
Materials & Design |
Abbreviated Journal |
Mater. Des. |
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Volume |
186 |
Issue |
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Pages |
108337 - 10pp |
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Keywords |
He-3 solid targets; Quasistatic magnetron sputtering; Low gas consumption; Nuclear reactions; Inverse kinematics; Target stability |
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Abstract |
Nanoporous solids that stabilize trapped gas nanobubbles open new possibilities to fabricate solid targets for nuclear reactions. A methodology is described based on the magnetron sputtering (MS) technique operated under quasistatic flux conditions to produce such nanocomposites films with He-3 contents of up to 16 at.% in an amorphous-silicon matrix. In addition to the characteristic low pressure (3-6 Pa) needed for the gas discharge, the method ensures almost complete reduction of the process gas flow during film fabrication. The method could produce similar materials to those obtained under classical dynamic flux conditions for MS. The drastic reduction (>99.5%) of the gas consumption is fundamental for the fabrication of targets with scarce and expensive gases. Si:He-3 and W:He-3 targets are presented together with their microstructural (scanning and transmission electron microscopy, SEM and TEM respectively) and compositional (Ion Beam Analysis, IBA) characterization. The He-3 content achieved was over 1 x 10(18) at/cm(2) for film thicknesses between 1.5 and 3 μm for both Si and W matrices. First experiments to probe the stability of the targets for nuclear reaction studies in inverse kinematics configurations are presented. |
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Address |
[Fernandez, Asuncion; Hufschmidt, Dirk; Godinho, Vanda; Jimenez de Haro, Maria C.; Feria, David] Univ Seville, CSIC, Inst Ciencia Mat Sevilla, Avda Amer Vespucio 49, Seville 41092, Spain, Email: asuncion@icmse.csic.es |
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Elsevier Sci Ltd |
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English |
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ISSN |
0264-1275 |
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Conference |
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Notes |
WOS:000505221700053 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4239 |
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Permanent link to this record |
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Author |
Hernandez, E.; Vijande, J.; Valcarce, A.; Richard, J.M. |
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Title |
Spectroscopy, lifetime and decay modes of the T-bb(-) tetraquark |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
800 |
Issue |
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Pages |
135073 - 9pp |
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Keywords |
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Abstract |
We present the first full-fledged study of the flavor-exotic isoscalar T-bb(-) equivalent to bb (u) over bar(d) over bar tetraquark with spin and parity J(P) = 1(+). We report accurate solutions of the four-body problem in a quark model, characterizing the structure of the state as a function of the ratio M-Q/m(q) of the heavy to light quark masses. For such a standard constituent model, T-bb(-) lies approximately 150 MeV below the strong decay threshold B- (B) over bar*(0) and 105 MeV below the electromagnetic decay threshold B- (B) over bar (0)gamma. We evaluate the lifetime of T-bb(-), identifying the promising decay modes where the tetraquark might be looked for in future experiments. Its total decay width is Gamma approximate to 87 x 10(-15) GeV and therefore its lifetime tau approximate to 7.6 ps. The promising final states are B*(-) D*(+) l (v) over bar (l) and (B) over bar*(0) l (v) over bar (l) among the semileptonic decays, and B*(-) D*(+) D-s*(-), (B) over bar*(0) D*(0) D-s*(-), and B*(-) D*(+) rho(-) among the nonleptonic ones. The semileptonic decay to the isoscalar J(P) = 0(+) tetraquark T-bc(0) is also relevant but it is not found to be dominant. There is a broad consensus about the existence of this tetraquark, and its detection will validate our understanding of the low-energy realizations of Quantum Chromodynamics (QCD) in the multiquark sector. |
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Address |
[Hernandez, E.; Valcarce, A.] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: gajatee@usal.es; |
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Elsevier |
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English |
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Series Volume |
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ISSN |
0370-2693 |
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Conference |
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Notes |
WOS:000503832500055 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4240 |
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Permanent link to this record |
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Author |
ATLAS Collaboration (Aad, G. et al); Alvarez Piqueras, D.; Aparisi Pozo, J.A.; Bailey, A.J.; Cabrera Urban, S.; Castillo, F.L.; Castillo Gimenez, V.; Cerda Alberich, L.; Costa, M.J.; Escobar, C.; Estrada Pastor, O.; Ferrer, A.; Fiorini, L.; Fullana Torregrosa, E.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Gonzalvo Rodriguez, G.R.; Guerrero Rojas, J.G.; Higon-Rodriguez, E.; Lacasta, C.; Lozano Bahilo, J.J.; Madaffari, D.; Mamuzic, J.; Marti-Garcia, S.; Melini, D.; Miñano, M.; Mitsou, V.A.; Rodriguez Bosca, S.; Rodriguez Rodriguez, D.; Ruiz-Martinez, A.; Salt, J.; Santra, A.; Soldevila, U.; Sanchez, J.; Valero, A.; Valls Ferrer, J.A.; Vos, M. |
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Title |
Searches for lepton-flavour-violating decays of the Higgs boson in root s=13 TeV pp collisions with the ATLAS detector |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
800 |
Issue |
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Pages |
135069 - 23pp |
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Keywords |
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Abstract |
This Letter presents direct searches for lepton flavour violation in Higgs boson decays, H -> e tau and H -> μtau, performed with the ATLAS detector at the LHC. The searches are based on a data sample of proton-proton collisions at a centre-of-mass energy root s = 13 TeV, corresponding to an integrated luminosity of 36.1 fb(-1). No significant excess is observed above the expected background from Standard Model processes. The observed (median expected) 95% confidence-level upper limits on the lepton-flavour-violating branching ratios are 0.47%(0.34(-0.10)(+0.13)%) and 0.28%(0.37(-0.10)(+0.14)%) for H -> e tau and H -> μtau, respectively. |
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Address |
[Deliot, F.; Duvnjak, D.; Jackson, P.; Oliver, J. L.; Petridis, A.; Qureshi, A.; Sharma, A. S.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia |
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Publisher |
Elsevier |
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English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Edition |
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ISSN |
0370-2693 |
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Expedition |
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Conference |
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Notes |
WOS:000503832500048 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4241 |
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Permanent link to this record |
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Author |
ATLAS Collaboration (Aad, G. et al); Alvarez Piqueras, D.; Aparisi Pozo, J.A.; Bailey, A.J.; Cabrera Urban, S.; Castillo, F.L.; Castillo Gimenez, V.; Cerda Alberich, L.; Costa, M.J.; Escobar, C.; Estrada Pastor, O.; Ferrer, A.; Fiorini, L.; Fullana Torregrosa, E.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Gonzalvo Rodriguez, G.R.; Guerrero Rojas, J.G.; Higon-Rodriguez, E.; Lacasta, C.; Lozano Bahilo, J.J.; Madaffari, D.; Mamuzic, J.; Marti-Garcia, S.; Melini, D.; Miñano, M.; Mitsou, V.A.; Rodriguez Bosca, S.; Rodriguez Rodriguez, D.; Ruiz-Martinez, A.; Salt, J.; Santra, A.; Soldevila, U.; Sanchez, J.; Valero, A.; Valls Ferrer, J.A.; Vos, M. |
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Title |
Search for flavour-changing neutral currents in processes with one top quark and a photon using 81 fb(-1) of pp collisions at root s=13 TeV with the ATLAS experiment |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
800 |
Issue |
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Pages |
135082 - 21pp |
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Keywords |
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Abstract |
A search for flavour-changing neutral current (FCNC) events via the coupling of a top quark, a photon, and an up or charm quark is presented using 81 fb(-1) of proton-proton collision data taken at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Events with a photon, an electron or muon, a b-tagged jet, and missing transverse momentum are selected. A neural network based on kinematic variables differentiates between events from signal and background processes. The data are consistent with the background-only hypothesis, and limits are set on the strength of the tq gamma coupling in an effective field theory. These are also interpreted as 95% CL upper limits on the cross section for FCNC t gamma production via a left-handed (right-handed) tu gamma coupling of 36 fb (78 fb) and on the branching ratio for t -> gamma u of 2.8 x 10(-5) (6.1 x 10(-5)). In addition, they are interpreted as 95% CL upper limits on the cross section for FCNC t gamma production via a left-handed (right-handed) tc.coupling of 40 fb (33 fb) and on the branching ratio for t -> gamma c of 22 x 10(-5) (18 x 10(-5)). |
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Address |
[Deliot, F.; Duvnjak, D.; Jackson, P.; Oliver, J. L.; Petridis, A.; Qureshi, A.; Sharma, A. S.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000503832500051 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4242 |
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Permanent link to this record |
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Author |
ATLAS Collaboration (Aad, G. et al); Alvarez Piqueras, D.; Aparisi Pozo, J.A.; Bailey, A.J.; Cabrera Urban, S.; Castillo, F.L.; Castillo Gimenez, V.; Cerda Alberich, L.; Costa, M.J.; Escobar, C.; Estrada Pastor, O.; Ferrer, A.; Fiorini, L.; Fullana Torregrosa, E.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Gonzalvo Rodriguez, G.R.; Guerrero Rojas, J.G.; Higon-Rodriguez, E.; Lacasta, C.; Lozano Bahilo, J.J.; Madaffari, D.; Mamuzic, J.; Marti-Garcia, S.; Melini, D.; Miñano, M.; Mitsou, V.A.; Rodriguez Bosca, S.; Rodriguez Rodriguez, D.; Ruiz-Martinez, A.; Salt, J.; Santra, A.; Soldevila, U.; Sanchez, J.; Valero, A.; Valls Ferrer, J.A.; Vos, M. |
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Title |
Combination of searches for Higgs boson pairs in pp collisions at root s=13 TeV with the ATLAS detector |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
800 |
Issue |
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Pages |
135103 - 23pp |
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Keywords |
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Abstract |
This letter presents a combination of searches for Higgs boson pair production using up to 36.1 fb(-1) of proton-proton collision data at a centre-of-mass energy root s = 13 TeV recorded with the ATLAS detector at the LHC. The combination is performed using six analyses searching for Higgs boson pairs decaying into the b (b) over barb (b) over bar, b (b) over barW(+)W(-), b (b) over bar tau(+)tau(-), W+W-W+W-, b (b) over bar gamma gamma and W+W-gamma gamma final states. Results are presented for non-resonant and resonant Higgs boson pair production modes. No statistically significant excess in data above the Standard Model predictions is found. The combined observed (expected) limit at 95% confidence level on the non-resonant Higgs boson pair production cross-section is 6.9 (10) times the predicted Standard Model cross-section. Limits are also set on the ratio (kappa(lambda)) of the Higgs boson self-coupling to its Standard Model value. This ratio is constrained at 95% confidence level in observation (expectation) to -5.0 < kappa(lambda) < 12.0 (-5.8 < kappa(lambda) < 12.0). In addition, limits are set on the production of narrow scalar resonances and spin-2 Kaluza-Klein Randall-Sundrum gravitons. Exclusion regions are also provided in the parameter space of the habemus Minimal Supersymmetric Standard Model and the Electroweak Singlet Model. |
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Address |
[Deliot, F.; Duvnjak, D.; Jackson, P.; Oliver, J. L.; Petridis, A.; Qureshi, A.; Sharma, A. S.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0370-2693 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000503832500009 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4243 |
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Permanent link to this record |