| 1 | AppelK,HakenW.Every planar map is four colorable. Part I: Discharging[J].Illinois Journal of Mathematics,1977,21(3):429-490. | 
																													
																						| 2 | AppelK,HakenW,KochJ.Every planar map is four colorable. Part Ⅱ: Reducibility[J].Illinois Journal of Mathematics,1977,21(3):491-567. | 
																													
																						| 3 | TutteW T.A contribution to the theory of chromatic polynomials[J].Canadian Journal of Mathematics,1954,6,80-91. doi: 10.4153/CJM-1954-010-9
 | 
																													
																						| 4 | TutteW T.On the algebraic theory of graph colourings[J].Journal of Combinatorial Theory,1966,1(1):15-50. doi: 10.1016/S0021-9800(66)80004-2
 | 
																													
																						| 5 | BondyJ,MurtyU.Graph Theory with Applications[M].New York:Elsevier,1976. | 
																													
																						| 6 | Lai H J, Luo R, Zhang C Q. Integer flows and orientations [M]//Beineke L W, Wilson RJ. (eds.) Topics in Chromatic Graph Theory, Cambridge: Cambridge University Press, 2015:181-198. | 
																													
																						| 7 | JaegerF.Flows and generalized coloring theorems in graphs[J].Journal of Combinatorial Theory, Series B,1979,26(2):205-216. doi: 10.1016/0095-8956(79)90057-1
 | 
																													
																						| 8 | SeymourP D.Nowhere-zero 6-flows[J].Journal of Combinatorial Theory, Series B,1981,30(2):130-135. doi: 10.1016/0095-8956(81)90058-7
 | 
																													
																						| 9 | FleischnerH.Eine gemeinsame basis für die theorie der eulerschen graphen und den Satz von petersen[J].Monatshefte für Mathematik,1976,81,267-278. | 
																													
																						| 10 | ZhangC Q.Integer Flows and Cycle Covers of Graphs[M].New York:Marcel Dekker, Inc,1997. | 
																													
																						| 11 | Jaeger F. Nowhere-zero flow problems [M]//Beineke L W, Wilson R J. (eds.) Selected Topicsin Graph Theory 3, London: Academic Press, 1988: 71-95. | 
																													
																						| 12 | MöllerM,CarstensH G,BrinkmannG.Nowhere-zero flows in low genus graphs[J].Journal of Graph Theory,1988,12(2):183-190. doi: 10.1002/jgt.3190120208
 | 
																													
																						| 13 | Celmins U A. On cubic graphs that do not have an edge 3-coloring[D]. Waterloo: University of Waterloo, 1984. | 
																													
																						| 14 | Jensen T R. Tutte's $k$-flow problems[D]. Denmark: Ordense University, 1985. | 
																													
																						| 15 | KocholM.Reduction of the 5-flow conjecture to cyclically 6-edge-connected snarks[J].Journal of Combinatorial Theory, Series B,2004,90(1):139-145. doi: 10.1016/S0095-8956(03)00080-7
 | 
																													
																						| 16 | KocholM.Decomposition formulas for the flow polynomial[J].European Journal of Combinatorics,2005,26(7):1086-1093. doi: 10.1016/j.ejc.2004.05.004
 | 
																													
																						| 17 | KocholM.Restrictions on smallest counterexamples to the 5-flow conjecture[J].Combinatorica,2006,26,83-89. doi: 10.1007/s00493-006-0006-1
 | 
																													
																						| 18 | KocholM.Smallest counterexample to the 5-flow conjecture has girth at least eleven[J].Journal of Combinatorial Theory, Series B,2010,100(4):381-389. doi: 10.1016/j.jctb.2009.12.001
 | 
																													
																						| 19 | Korcsok P. Minimal counterexamples to flow conjectures[D]. Prague: Charles University, 2015. | 
																													
																						| 20 | MazzuoccoloG,SteffenE.Nowhere-zero 5-flows on cubic graphs with oddness 4[J].Journal of Graph Theory,2017,85(2):363-371. doi: 10.1002/jgt.22065
 | 
																													
																						| 21 | SteffenE.Tutte's 5-flow conjecture for highly cyclically connected cubic graphs[J].Discrete Mathematics,2010,310(3):385-389. doi: 10.1016/j.disc.2009.03.014
 | 
																													
																						| 22 | SteffenE.Tutte's 5-flow conjecture for graphs of nonorientable genus 5[J].Journal of Graph Theory,1996,22(4):309-319. doi: 10.1002/(SICI)1097-0118(199608)22:4<309::AID-JGT5>3.0.CO;2-P
 | 
																													
																						| 23 | ErdősP,SachsH.Reguläre graphen gegebener taillenweite mit minimaler knotenzahl[J].Wissenschaftliche Zeitschrift/Martin-Luther-Universit$\ddot{a}$t, Halle-Wittenberg Mathematisch-naturwissenschaftliche Reihe,1963,12,251-257. | 
																													
																						| 24 | BalabanA T.A trivalent graph of girth ten[J].Journal of Combinatorial Theory, Series B,1972,12(1):1-5. | 
																													
																						| 25 | McKay B, Myrvold W, Nadon J. Fast backtracking principles applied to find new cages[C]//Proccedings of 9th Annual ACM-SIAM Symposium on Discrete Algorithms, 1998: 188-191. | 
																													
																						| 26 | SteinbergK.Tutte's 5-flow conjecture for the projective plane[J].Journal of Graph Theory,1984,8,277-285. doi: 10.1002/jgt.3190080208
 | 
																													
																						| 27 | YoungsJ W T.Minimal imbeddings and the genus of a graph[J].Journal of Mathematics and Mechanics,1963,12(2):303-315. |