Finding Aid to the Nathan Isgur Papers

Nathan Isgur, Martha Krebs, Christoph LeemannNathan IsgurNathan Isgur, Energy Secretary Robert Skunda, Hermann Grunder

Photos:

(left) November 23, 1993, Martha Krebs, director of the Department of Energy's Office of Energy Research in Washington, signs the final cryomodule, Golden Girl, during the Insitutional Plan Review Tour. Christoph Leemann and Nathan Isgur (foreground) look on. 
(center) Nathan Isgur's Jefferson Lab photo.
(right) Nathan Isgur with Energy Secretary Robert Skunda (center) and CEBAF director Hermann Grunder (right), October 1994 (credit: Jefferson Lab)

Table of Contents

Repository: Thomas Jefferson National Accelerator Facility
  JLAB History Archives Project
  12000 Jefferson Ave., Room L203A
  Newport News, VA 23606
  Phone: (757) 269-7805
  Fax: (757) 269-5427
  Email: history@jlab.org
  https://www.jlab.org/info_resources/archives
Creator: Nathan Isgur
Title: Nathan Isgur Papers
Dates: Mid 1970s - 2001
Size: Physical: 18 Hollinger boxes, 1 tube; 7.67 linear feet Digital: 126 files, 107 megabytes
Materials in collection: Correspondence, drafts, printed material, digital archive of presentations
Abstract: Nathan Isgur was a leading theoretical physicists who worked at Jefferson Lab from 1990 to 2001. He was the Lab's chief scientists and Theory Group Leader. During his career, Dr. Isgur greatly contributed to the understanding of the quark structure of matter.
Identification number: JLS.003
Location: Digital collection location in the Jefferson Lab Document Management System. Non-digital items located in the Jefferson Lab Archives Room.
Language: English

Biographical Note

Dr. Nathan Isgur, born 1947 in South Houston, Texas, remained in residence of his home town through the completion of his high school education. He later studied at the California Institute of Technology where he received his B.S. in physics in 1968. He began his doctoral program at the University of California, Berkley soon after, but chose to transfer to the University of Toronto to continue his graduate studies after having failed to receive a draft deferment.1 Dr. Isgur received his Ph.D. in Particle Theory in 1974. He served as a professor of physics at the University of Toronto from 1976 to 1990.

In 1990, he began his work at CEBAF (Continuous Electron Beam Accelerator Facility), later known as the Thomas Jefferson National Accelerator Facility2 serving as the Lab's Theory Group Leader. He was also on the faculty at the College of William & Mary in Williamsburg, Virginia as a Governor's Distinguished Professor. Dr. Isgur, a leading theoretical physicist, was formally named Chief Scientist in 1996, which he held until his untimely death in 2001. In this role, Dr. Isgur advised the Lab's Director on the planning and interpretation of the Jefferson Lab experimental program and served on the Lab's Director's Council.2

During his career, Dr. Isgur published over 100 papers on the quark structure of matter and was well known for his work on the excited states of the proton.2 In 1978, he and Gabriel Karl proposed the 3-quark model that is now the standard model of the proton and neutron. 3 Dr. Isgur's work with Mark Wise led to the discovery of heavy quark symmetry in chromodynamics.2

Dr. Isgur's work earned him a number of awards, including the Steacie Price (1986), the Herzberg Medal (1984), the Rutherford Medal (1989)3, and the Sakurai Prize (2001). Dr. Isgur was married to Karin Bergsagel, with whom he had two sons.

He died in 2001 of complications from multiple myeloma.

References

  1. Karl, Gabriel and Sinervo, Pekka. "In Memoriam Nathan Isgur, 1947 – 2001," The Canadian Association of Physicists. http://www.cap.ca/pic/archives/57.5(2001)/memoriam.html (accessed 24 September 2015)
  2. Jefferson Lab. "Dr. Nathan Isgur: Chief Scientist, Thomas Jefferson National Accelerator Facility," http://www.jlab.org/div_dept/dir_off/directors/NIbio.html (accessed 11 March, 2016)
  3. Science.ca. "Nathan Isgur: General Physics, Subatomic Particles, Optics, Biophysics, Theoretical Physics. Developed theory for the 3-quark model," http://www.science.ca/scientists/scientistprofile.php?pID=177 (accessed 10 March 2016)

 


Scope and Content

This collection primarily consists of materials related to Dr. Isgur's work at Jefferson Lab, though also including some records from his earlier work at the University of Toronto. The bulk of the collection consists of Dr. Isgur's publications and research notes, most of which are handwritten and undated. Also included are correspondence, drafts of Dr. Isgur's writings, as well as published articles that contain notes and editorial comments. The collection also consists of material from the many conferences and lectures that Dr. Isgur attended including notes, transparencies*, lecture and presentation outlines and related material.

*Transparencies of presentations at conferences/seminars/workshops have been digitized. Hard copies are available in the Archives; digital access available upon request.

 


Arrangement

Series I: Notes. Included in this series are notes by Dr. Isgur; some in collaboration with colleagues. There are many unlabeled and undated notes, and those are in their own sub-series. Any collaboration correspondences in reference to the sub-series of this group are included in the category in which they were found when the collection was accessioned.*

  • Sub-series A: QCD & P. Geiger
  • Sub-series B: Scalar Mesons
  • Sub-series C: Multiquark Hadrons
  • Sub-series D: Baryons
  • Sub-series E: Known Subjects by date
  • Sub-series F: Undated
    • Sub-subseries i: Labelled Topics
    • Sub-subseries ii: Unlabeled Topics

Series II: Publications. Included in this series are drafts, correspondence, revisions, and notes for published copies of papers written for journals and proceedings of conferences Dr. Isgur attended. This collection is in chronological order, as best as could be deciphered. Those without dates are at the end of the given series. A master list is within the collection.

Series III: Correspondence. This series is inclusive of various correspondences of Dr. Isgur not relating to a specific project.

Series IV: Educational Course Materials. These papers appear to have been used by Dr. Isgur as a student and as a professor. This series has a large digital facet.

Series V: Miscellany. This series covers articles written about Dr. Isgur, articles he refereed, and various notes and information regarding various facets of Jefferson Lab.

Series VI: Presentations/Lectures. This series is subdivided into two subseries: dated and undated. The undated series is arranged alphabetically by the lecture title.

  • Sub-series A: Dated
  • Sub-series B: Not Dated

*Records are arranged chronologically by date of creation within each series. If the date is unknown, records are grouped by topic. For records lacking date and title, they are in the original, unsorted order.

 


Restrictions

Access Restrictions

  • The collection may be used solely for noncommercial, educational, and research purposes by researchers and historians. Please contact the Jefferson Lab Records Management Office if you would like to use the collection.

Use Restrictions

  • Jefferson Lab is providing access to the materials in the Archives collections solely for noncommercial educational and research purposes. The unauthorized use, including, but not limited to, publication of the materials without the prior written permission of Jefferson Lab, is strictly prohibited. All inquiries regarding permission to publish should be submitted in writing to the Archivist. In addition to consent from Jefferson Lab, permission of the copyright owner (if not Jefferson Lab) and/or any holder of other rights (such as publicity and/or privacy rights) may also be required for reproduction, publication, distribution, and other uses. Responsibility for making an independent legal assessment of any item and securing any necessary permissions rests with the persons desiring to publish the item. Jefferson Lab makes no warranty or guarantee as to the accuracy of the materials or their fitness for a particular purpose.

 


Controlled Access Terms

CEBAF News/On Target (Collection #JL.006A)
Continuous Electron Beam Accelerator Facility (CEBAF)
Form Factors
Heavy Quarks
Isgur, Nathan
Jefferson Lab (U.S.)
Quantum Chromodynamics (QCD)
Theoretical Physics
Thomas Jefferson National Accelerator Facility (U.S.)
TRIUMF

 


Administration Information

Preferred Citation: 
[Identification of Item], Box [insert number], Folder [insert number and title], The Papers of Nathan Isgur, Jefferson Lab Archives, Thomas Jefferson National Accelerator Facility, 12000 Jefferson Ave., Room L203A, Newport News, VA, 23606

Acquisition Information:
This collection was acquired from various sources including the Library. Dr. Isgur's wife, Karin, donated a set of his writings.

Processing History:
This collection was processed by Melissa Erlandson in October-November, 2016.

Acknowledgement:
This collection was supported in part by a grant from the History Programs, American Institute of Physics.

 


Box and Container Listing 
Series I: Notes
Box 1
  • Sub-series A: QCD and P. Geiger
  • Folder 1: Pauli Force and NN Force
  • Folder 2: "Basic Calc"
  • Folder 3: On a Static Definition
  • Folder 4: Gauge Invariance
  • Folder 5: Making Pair Creation gauge Invariance
  • Folder 6: Correspondence with Paul Geiger
  • Folder 7: "On a gauge invariance model"
  • Folder 8: Screen Shots & Equations
  • Sub-series B: Scalar Mesons
  • Folder 9: Scalar Mesons, 1980s
  • Folder 10: Wave Functions
  • Sub-series C: Multiquark Hadrons
  • Folder 11: Multiquark Hadron
  • Folder 12: Multiquark Hadrons
  • Folder 13: Multiquark Hadrons, early years - Part 1
  • Folder 14: Multiquark Hadrons, early years - Part 2
Box 2
  • Sub-Series D: Baryons
  • Folder 1: Baryons "Part 1"
  • Folder 2: Baryons, Positive Parity
  • Folder 3: Baryons Misc.
  • Folder 4: Baryons Misc.
  • Folder 5: Baryons Undated
  • Folder 6: Baryons
  • Folder 7: Baryons
  • Folder 8: LS Baryons
Box 3
  • Sub-series E: Known Subjects, Chronological
  • Folder 1: Loose Notes
  • Folder 2: Form Factor Types, 1983
  • Folder 3: Soft and Nuclear Factor, c. 1987
  • Folder 4: Nucleon Soft Form Factor
  • Folder 5: "NTX", 1988
  • Folder 6: Transparencies, 1988-1989
  • Folder 7: φ Spinless, Bjorken Sum Rule, c. 1990
  • Folder 8: Nonresonant Heavy Quark Decay, 1990
  • Folder 9: Continua: Nonresonant Decay Bι→DjH Transitions 1996-1997
  • Folder 10: Inelastic Channels, 1997
Box 4
  • Folder 1: Form Factors of the Nucleon at Small Momentum Transfers, 1998
  • Folder 2: OZI vs. lattice QCD 1999-2000
  • Folder 3: Duality, early 2000s
  • Folder 4: 1/NC vs. Instantons, c. 2000
  • Folder 5: Heavy Quarks, c. 2000
  • Folder 6: Duality Types, 2000-2001
  • Sub-series F: Undated
    • Sub-subseries i: Labeled Topics
    • Folder 7: Mesons and Baryon Resonance
    • Folder 8: Notes on Regge Theory and Helicity Amplitude
    • Folder 9: Zuminos Study and Notes
    • Folder 10: Model for Transparency
    • Folder 11: Hard QCD Outline and Lepton-Hadron Scattering
Box 5
  • Folder 1: LS Inversion, Part 1
  • Folder 2: LS Inversion, Part 2
  • Folder 3: Form Factors & ISGW2
  • Folder 4: "Config Mix, etc."
Box 6
  • Folder 1: Deep Elastic Heavy Quarks and Quark Jets
  • Folder 2: Non-resonant cdcs
  • Folder 3: Form Factors
  • Folder 4: Pion Form Factors
  • Folder 5: Form Factors, Misc
    • Sub-subseries ii: Unlabeled
    • Folder 6: Undated, Unlabeled Notes
    • Folder 7: "Random Ideas"
    • Folder 8: Misc.
    • Folder 9: "Misc. Notes & Ideas"
    • Folder 10: Notes
Box 7
  • Folder 1: Undated, Unlabeled Notes
  • Folder 2: Undated, Unlabeled Notes
  • Folder 3: Undated, Unlabeled Notes
  • Folder 4: Undated, Unlabeled Notes
  • Folder 5: Undated, Unlabeled Notes
  • Folder 6: Undated, Unlabeled Notes
  • Folder 7: Undated, Unlabeled Notes
  • Folder 8: Undated, Unlabeled Notes
  • Folder 9: Undated, Unlabeled Notes
Box 8
  • Folder 1: Undated, Unlabeled Notes
  • Folder 2: Undated, Unlabeled Notes
  • Folder 3: Undated, Unlabeled Notes
 
Series II: Publications
  • Folder 4: Publications Master Listing
  • Folder 5: "K 0/L-K 0/S Mass Difference", 1972
  • Folder 6: "Octet Enhancement"
  • Folder 7: "Quark Model for K13 Form Factors", 1975
  • Folder 8: "A Broken SU(2) Phenomenology for Weather Interaction", 1977
  • Folder 9: "P-wave Baryons in the Quark Model", 1978
  • Folder 10: "Violations of SU (6) Selection Rules from Quark Hyperfinite Interactions"
  • Folder 11: "Positive Parity Excited Baryons in a Quark Model"
  • Folder 12: "Neutron Charge Form Factors"
  • Folder 13: "Isospin-Violating Mass Differences in Mixing Meson Nonets", c. 1981
  • Folder 14: "Baryon Decays in a Quark Model with Chromodynamics"
  • Folder 15: "Comment on the Magnetic Dipole Decay of Mesons"
  • Folder 16: "Two Photon Decay of the Pseudoscalar Mesons"
  • Folder 17: "Low Energy Hadron Dynamics with Medium Mass Quarks"
  • Folder 18: "Ground State Baryons and Magnetic Moments", 1980
  • Folder 19: "Baryons with Strangeness and Charm in a Quark Model"
  • Folder 20: "Beyond the Wave Function at the Origin: Some Momentum-Dependent Effects in the Non-Relativistic Quark Model", 1981
  • Folder 21: "Difficulties with the Mixing Formalism for Decays Violating Zweig's Rule", c. 1983
  • Folder 22: "On the Consistency of Chiral Symmetry and the Quark Model in Photon Decay", 1982
  • Folder 23: "Asymptomatic Q2 for Exclusive Process", 1984
  • Folder 24: "Quark Model Predictions"
  • Folder 25: "Weak Transition Form Factors between Heavy Mesons"
  • Folder 26: "Hadronic Physics at 1 GeV: Open Questions", 1988
  • Folder 27: "Polarization in B→D*e ¯ve and →K*e+ve" 1989
  • Folder 28: "From Chromodynamics to Hadron Physics towards Nuclear Physics"
  • Folder 29: "Influence of the B* Resonance on B→Πev*e
Box 9
  • Folder 1: "Transition Moments"
  • Folder 2: "Weak Transition", 1 of 2
  • Folder 3: "Weak Transition", 2 of 2
  • Folder 4: "Quenched Approximation in the Quark Model"
  • Folder 5: "Heavy Baryon Weak Form Factors"
  • Folder 6: "Heavy Quark Symmetries in Form Factors at Large"
Box 10
  • Folder 1: "Spectroscopy with Heavy Quark Symmetry"
  • Folder 2: "How the OZI Rule Evades Large Loop Corrections"
  • Folder 3: "Scalar Mesons" 1 of 2
  • Folder 4: "Scalar Mesons" 2 of 2
Box 11
  • Folder 1: "Factorization and Heavy Quark Symmetry in Hadronic B-Meson Decays", 1 of 3
  • Folder 2: "Factorization and Heavy Quark Symmetry in Hadronic B-Meson Decays", 2 of 3
  • Folder 3: "Factorization and Heavy Quark Symmetry in Hadronic B-Meson Decays", 3 of 3
  • Folder 4: "End-point Region of the Electron Spectrum in Inclusive Semileptonic Heavy Quark Decay"
  • Folder 5: "Comment Regarding Bounds Upon Heavy Meson Form Factors"
Box 12
  • Folder 1: "When Can Hadronic Loops Scuttle the OZI Rule"/"Reconciling The OZI Rule with Strong Pair Creation"
  • Folder 2: "Strangeness of the Proton in the Quark Model"
  • Folder 3: "Semileptonic Decays in the Quark Model: An Update", 1 of 4
  • Folder 4: "Semileptonic Decays in the Quark Model: An Update", 2 of 4
  • Folder 5: "Semileptonic Decays in the Quark Model: An Update", 3 of 4
Box 13
  • Folder 1: "Semileptonic Decays in the Quark Model: An Update", 4 of 4
  • Folder 2: "Comment on: Sigma Mesons"
  • Folder 3: "Exclusive v. Inclusive B Decays in the Quark Model"
  • Folder 4: "Strange Hadronic Loops of the Proton: A Quark Model Calculation"
  • Folder 5: "Spin-Orbit Inversion of Excited Heavy Quark Mesons"
  • Folder 6: "Duality-violating 1/mQ Effects in Heavy Quark Decay"
  • Folder 7: "Duality in Inclusive Semileptonic Heavy Quark Decay"
  • Folder 8: "Valence Quark Spin Distribution Functions", 1 of 2
Box 14
  • Folder 1: "Valence Quark Spin Distribution Functions", 2 of 2
  • Folder 2: "Comment on "Valence QCD: Connecting QCD to the Quark Model""
  • Folder 3: "Nonresonant States in Semileptonic Heavy Quark Decay"
  • Folder 4: "Hardon Physics with Chromodynamics"
  • Folder 5: "Critique of a Pion Exchange Model for Interquark Forces"
  • Folder 6: "Exchange Currents in Baryons", by A.J. Buchmann
  • Folder 7: "Interpreting the Neutron's Electric Form Factor: Rest Frame Distribution or Foldy Term?"
  • Folder 8: "On the Origin of the OZI Rule"
  • Folder 9: "Soft QCD: Low Energy Hadron Physics with Chromodynamics"
  • Folder 10: "Baryons with Heavy Quark Symmetry"
Box 15
  • Folder 1: "Quark Model Predictions for the Electron Energy Spectrum", 1 of 2
  • Folder 2: "Quark Model Predictions for the Electron Energy Spectrum", 2 of 2
  • Folder 3: "What's New in the Old Spectroscopy?"
  • Folder 4: "Hadron Spectroscopy: An Overview with Strings Attached"
  • Folder 5: "Quark Exchange Forces from a Heavy Quark Perspective"
  • Folder 6: "Heavy Quark Symmetry"
  • Folder 7: "Introduction to the Quark Model for Baryons"
Box 16
  • Folder 1: "Baryons & QCD"
  • Folder 2: "Baryons with Heavy Quark Symmetry"
  • Folder 3: "Hadron Spectroscopy and Structure"
  • Folder 4: "The Flux Tube Model"
  • Folder 5: "Baryons: The Promise, the Problems, and the Prospects"
  • Folder 6: "The Quark Structure of Matter"
  • Folder 7: "Spectroscopy: An Introduction and Overview"
  • Folder 8: "Excited Charm Baryons in the Semileptonic Λb Decay and their Contribution to a Bjorken Sum Rule"
  • Folder 9: "Hadron Spectroscopy", PANIC XII
  • Folder 10: "Strangeness in the Nucleon; or, The Quark Model Beyond Valence Approximation"
  • Folder 11: "Why N* Are So Important"
  • Folder 12: McGraw Hill Encyclopedic Entry, 1992
  • Folder 13: McGraw Hill Encyclopedic Entry, 1996
  • Folder 14: "Strangeness in the Nucleon; or, The Quark Model Beyond Valence Approximation"
Box 17
  • Folder 1: "Duality in B Decay"
  • Folder 2: "Scalar Meson in φ Radiative Decay"
  • Folder 3: "Physics Today", August 1993
  • Folder 4: "A Subnuclear Physics Manifesto"
  • Folder 5: "The Quark Structure of Matter", Tokyo 1996
  • Folder 6: "Nonresonant States", 1996
  • Folder 7: "The Spin of the Proton"
  • Folder 8: "Spin Structure of the Proton"
  • Folder 9: "The Proton's Spin: A Spectator's View"
  • Folder 10: "Models of Semileptonic Decay"
 
Series III: Correspondence
Box 18
  • Folder 1: Various
  • Folder 2: Frank Close
  • Folder 3: H.J. Schnitzer
  • Folder 4: S. Gerschtein
  • Folder 5: NSAC Meeting, Notes
  • Folder 6: Boulder Workshop, 20-22 September 1990
  • Folder 7: Hadron '91
  • folder 8: 4th IPNP, 23-29 May, 1991
  • Folder 9: Baryons '92
  • Folder 10: TRIUMF, Summer 1995
 
Series IV: Education Materials
  • Folder 11: Educational Materials
  • Folder 12: "Prof Isgur"
 
Series V: Miscellany
  • Folder 13: "On Target" 1999, 2001
Box 19
  • Folder 1: Refereed article for B. Schwarzschild
  • Folder 2: CEBAF-related
  • Folder 3: JLab-related
  • Folder 4: SURA-related
 
Series VI: Lectures and Presentations

Series is still processing and not yet available to the public.
Subseries A: Dated
  • Folder 5: Quarks & All That, 19 October 1978
  • Folder 6: International Symposium on Production and Decay of Heavy Hadrons, 20-23 May 1986
  • Folder 7: ISI - Torino, 9-12 November 1987
  • Folder 8: LEAR, 4 May 1988
  • Folder 9: Hadron '89: Concluding Remarks: Light Quarks and Glue (Theory)
  • Folder 10: DPF, 3-6 January 1990
  • Folder 11: PANIC XII 25-29 June 1990, MIT
  • Folder 12: b-Physics Workshop, Scotland, 1991, 1 of 2
  • Folder 13: b-Physics Workshop, Scotland, 1991, 2 of 2
  • Folder 14: QCD3 Lecture, 1991
  • Folder 15: INT N* Workshop, General, 1991
  • Folder 16: INT N* Workshop, CEBAF, 17-28 June 1991
Box 20
  • Folder 1: INT N* Workshop, Seattle, Summer Session, 1991, 1 of 2
  • Folder 2: INT N* Workshop, Seattle, Summer Session, 1991, 2 of 2
  • Folder 3: INT N* Grad Students/Summer School
  • Folder 4: Grunder Symposium, 9 December 1991
  • Folder 5: Experiments, 1992
  • Folder 6: Heavy Quark Symmetry, 23-25 January 1992
  • Folder 7: XXVI ICHEP, 6-12 August 1992, 1 of 2
  • Folder 8: XXVI ICHEP, 6-12 August 1992, 2 of 2
  • Folder 9: Strange Particle Production at CEBAF, 17 November 1993
  • Folder 10: What is NP?, 1994
  • Folder 11: A Puzzle in Strong Interactions, 24 January 1994
Box 21
  • Folder 1: QCD1, 31 January 1994
  • Folder 2: Few Body XIV, 26-31 May 1994
  • Folder 3: AAAS, Atlanta, February 1995Folder 4: TRIUMF, Summer 1995
  • Folder 5: Erice, 3-10 August 1995
  • Folder 6: Baryons '95, 3-7 October 1995
  • Folder 7: Chiral Dynamics (w. Aron Bernstein), 1996-2001
  • Folder 8: CEBAF Science Topics, 29 February 1996
  • Folder 9: Workshop N* Physics, September 1996
  • Folder 10: Where's the Glue?, December 1996
  • Folder 11: Quark Structure of Matter, December 1996
  • Folder 12: Medium Energy Seminar, 23 October 1997
  • Folder 13: Puzzles of the Strong Interactions, October 1998
  • Folder 14: CEBAF and Worldwide Labs, 19-20 October 1998
  • Folder 15: Quarks, Gluons, and the Nuclear Force, March 1999
  • Folder 16: 1999 Centennial Meeting, 20-26 March 1999
  • Sub-series B: Not Dated
  • Folder 17: Loose Slides
  • Folder 18: Baryons and QCD
  • Folder 19: CEBAF Scientific Goal
  • Folder 20: CEBAF: A Scientific Perspective
  • Folder 21: CEBAF at JLAB
  • Folder 22: Critique of OPE
  • Folder 23: Dressing the Baby, Part 2 (Lecture 3)
  • Folder 24: Experiments, etc.
  • Folder 25: Flux Tube Zero-Point, cont.
  • Folder 26: Future Directions of Nuclear Physics
Box 22
  • Folder 1: Hadron Structure with QCD
  • Folder 2: Heavy Quark Limit
  • Folder 3: Interpreting Gne
  • Folder 4: JLab "Campaigns"
  • Folder 5: "Los Alamos Incident"
  • Folder 6: Nature of the Nucleus
  • Folder 7: NSAC on Upgrade
  • Folder 8: A Molecular Physics Analogy
  • Folder 9: QCD2
  • Folder 10: QCD4 Lecture
  • Folder 11: Quark Exchange Forces
  • Folder 12: Quarks, Gluons, and All That Stuff
  • Folder 13: Quark Models for Mesons and Baryons with QCD
  • Folder 14: Quenched Lattice
  • Folder 15: Seeing Through the Meson Cloud
  • Folder 16: Semileptonic B and D Decays in the Quark Model
  • Folder 17: Soft QCD
  • Folder 18: Where are we now?
  • Folder 19: Demonstrative String (used to illustrate ideas)
Tube 1
  • Item 1: Where's the Glue?

 


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