### Complete Bibliography

[1] : “Horn sentences in identity theory,” J. Symb. Logic 24 : 4 (December 1959), pp. 306–310. MR 132691 Zbl 0114.24502 article

[2] : Two investigations on the borderline of logic and algebra. Ph.D. thesis, University of Michigan, 1959. Advised by R. C. Lyndon. MR 2612854 phdthesis

[3] : “Partition rings of cyclic groups of odd prime power order,” Can. J. Math. 13 (1961), pp. 373–391. MR 124419 Zbl 0100.03001 article

[4] : “On the group generated by a free semigroup,” Proc. Am. Math. Soc. 15 : 5 (1964), pp. 838–840. MR 168682 Zbl 0126.04701 article

[5] : “On properties of regressive sets,” Trans. Am. Math. Soc. 115 (1965), pp. 83–93. MR 230616 Zbl 0192.05202 article

[6] : “No recursively enumerable set is the union of finitely many immune retraceable sets,” Proc. Am. Math. Soc. 18 : 2 (1967), pp. 279–281. MR 207548 Zbl 0183.01402 article

[7] : “There exist two regressive sets whose intersection is not regressive,” J. Symb. Log. 32 : 3 (October 1967), pp. 322–324. MR 215711 Zbl 0192.05203 article

[8]
:
“On unsolvable groups of degree __\( p=4q+1 \)__, __\( p \)__ and __\( q \)__ primes,”
Can. J. Math.
19
(1967),
pp. 583–589.
MR
217165
Zbl
0166.01903
article

[9]
:
“On the equation __\( z_1^n z_2^n\cdots z_k^n = y^n \)__ in a free semigroup,”
Trans. Am. Math. Soc.
134 : 3
(December 1968),
pp. 461–470.
MR
230827
Zbl
0169.02703
article

[10] : “One-variable equations in free groups,” Proc. Am. Math. Soc. 19 : 4 (1968), pp. 912–918. MR 232826 Zbl 0159.30502 article

[11] : “On two variable equations in free groups,” Proc. Am. Math. Soc. 21 : 1 (1969), pp. 179–184. MR 257193 Zbl 0172.02701 article

[12] : “The conjugacy problem for the group of any tame alternating knot is solvable,” Proc. Am. Math. Soc. 33 : 2 (1972), pp. 329–336. MR 294460 Zbl 0243.20036 article

[13]
:
“On the conjugacy problem for knot groups,”
pp. 18
in
Conference in group theory
(Racine, WI, 28–30 June 1972).
Edited by R. W. Gatterdam and K. W. Weston.
Lecture Notes in Mathematics 319.
Springer (Berlin),
1973.
Abstract only.
Abstract for an article eventually published in *Math. Z.* **138**:3 (1974).
Zbl
0256.20045
incollection

[14]
:
“On the conjugacy problem for knot groups,”
Math. Z.
138 : 3
(1974),
pp. 273–294.
An abstract was published in *Conference in group theory* (1972).
MR
357622
Zbl
0276.20033
article

[15] : “Book review: J. N. Crossley, et al., ‘What is mathematical logic?’,” Math. Mag. 47 : 4 (September 1974), pp. 236–237. MR 1572110 article

[16] : “The existence of unavoidable sets of geographically good configurations,” Ill. J. Math. 20 : 2 (1976), pp. 218–297. MR 392641 Zbl 0322.05141 article

[17] : “Every planar map is four colorable,” Bull. Am. Math. Soc. 82 : 5 (September 1976), pp. 711–712. MR 424602 Zbl 0331.05106 article

[18] : “A proof of the four color theorem,” Discrete Math. 16 : 2 (October 1976), pp. 179–180. MR 543791 Zbl 0339.05109 article

[19] : “Every planar map is four colorable,” J. Recreat. Math. 9 : 3 (1976–1977), pp. 161–169. MR 543797 Zbl 0357.05043 article

[20]
:
“Every planar map is four colorable, I: Discharging,”
Ill. J. Math.
21 : 3
(1977),
pp. 429–490.
A microfiche supplement to both parts was published in *Ill. J. Math.* **21**:3 (1977).
MR
543792
Zbl
0387.05009
article

[21]
:
“Every planar map is four colorable, II: Reducibility,”
Ill. J. Math.
21 : 3
(1977),
pp. 491–567.
A microfiche supplement to both parts was published in *Ill. J. Math.* **21**:3 (1977).
MR
543793
Zbl
0387.05010
article

[22]
:
“The class check lists corresponding to the supplement to ‘Every planar map is four colorable. Part I and Part II’,”
Ill. J. Math.
21 : 3
(1977),
pp. C1–C210.
Microfiche supplement.
Extra material to accompany the supplement published in *Ill. J. Math.* **21**:3 (1977).
MR
543794
article

[23]
:
“Microfiche supplement to ‘Every planar map is four colorable. Part I and Part II’,”
Ill. J. Math.
21 : 3
(1977),
pp. 1–251.
Microfiche supplement.
Supplement to the two part article published as *Ill. J. Math.* **21**:3 (1977) and *Ill. J. Math.* **21**:3 (1977). A class check list was also published as *Ill. J. Math.* **21**:3 (1977).
MR
543795
article

[24] : “The solution of the four-color-map problem,” Sci. Amer. 237 : 4 (October 1977), pp. 108–121. MR 543796 article

[25] : “News & letters,” Math. Mag. 50 : 3 (May 1977), pp. 173–175. MR 1572218 article

[26] : “The four-color problem,” pp. 153–180 in Mathematics today: Twelve informal essays. Edited by L. A. Steen. Springer (Berlin), 1978. incollection

[27] : “An unavoidable set of configurations in planar triangulations,” J. Comb. Theory, Ser. B 26 : 1 (February 1979), pp. 1–21. MR 525813 Zbl 0407.05035 article

[28]
:
“Triangulation à __\( v_5 \)__ séparés dans le problème des quatre couleurs”
[Separated triangulation of __\( v_5 \)__ in the four-color problem],
J. Comb. Theory, Ser. B
27 : 2
(October 1979),
pp. 130–150.
MR
546856
Zbl
0344.05113
article

[29] : “Un nouveau type de preuve mathématique. Le théorème des quatre couleurs, II” [A new type of mathematical proof: The four-color theorem, II], Publ. Dép. Math., Lyon 16 : 3–4 (1979), pp. 81–88. In collaboration with W. Haken. MR 602656 Zbl 0455.05031 article

[30]
:
“Lifting surface groups to __\( \mathrm{SL}(2,\mathbb{C}) \)__,”
pp. 1–5
in
Kleinian groups and related topics
(Oaxtepec, Mexico, 10–14 August 1981).
Edited by D. M. Gallo and R. M. Porter.
Lecture Notes in Mathematics 971.
Springer (Berlin),
1983.
MR
690272
Zbl
0531.30037
incollection

[31] : “Artin groups and infinite Coxeter groups,” Invent. Math. 72 : 2 (June 1983), pp. 201–220. MR 700768 Zbl 0536.20019 article

[32] Contributions to group theory, published as Contemp. Math. 33. Issue edited by K. I. Appel, J. G. Ratcliffe, and P. E. Schupp. American Mathematical Society (Providence, RI), 1984. Papers dedicated to Roger C. Lyndon on the occasion of his sixty-fifth birthday. MR 767092 Zbl 0539.00007 book

[33] : “Roger C. Lyndon: A biographical and personal note,” pp. 1–10 in Contributions to group theory. Edited by K. I. Appel, J. G. Ratcliffe, and P. E. Schupp. Contemporary Mathematics 33. American Mathematical Society (Providence, RI), 1984. MR 767093 Zbl 0546.01008 incollection

[34] : “On Artin groups and Coxeter groups of large type,” pp. 50–78 in Contributions to group theory. Edited by K. I. Appel, J. G. Ratcliffe, and P. E. Schupp. Contemporary Mathematics 33. American Mathematical Society (Providence, RI), 1984. MR 767099 Zbl 0576.20021 incollection

[35] : “The four color proof suffices,” Math. Intell. 8 : 1 (1986), pp. 10–20. MR 823216 Zbl 0578.05022 article

[36] : Every planar map is four colorable. Contemporary Mathematics 98. American Mathematical Society (Providence, RI), 1989. With the collaboration of J. Koch. MR 1025335 Zbl 0681.05027 book