Cvetković, Dragoš Spectral theory of Smith graphs. (English) Zbl 1474.05243 Bull., Cl. Sci. Math. Nat., Sci. Math. 42, 19-40 (2017). MSC: 05C50 11D04 PDFBibTeX XMLCite \textit{D. Cvetković}, Bull., Cl. Sci. Math. Nat., Sci. Math. 42, 19--40 (2017; Zbl 1474.05243) Full Text: Link
Cvetković, Dragoš Three examples of a ground-breaking impact of the variable neighborhood search on investigations in graph theory. (English) Zbl 1461.05120 Bull., Cl. Sci. Math. Nat., Sci. Math. 41, 87-99 (2016). MSC: 05C50 05D99 PDFBibTeX XMLCite \textit{D. Cvetković}, Bull., Cl. Sci. Math. Nat., Sci. Math. 41, 87--99 (2016; Zbl 1461.05120) Full Text: Link
Cvetković, Dragoš Two mathematical papers relevant for the Hückel molecular orbital theory. (English) Zbl 1464.05061 MATCH Commun. Math. Comput. Chem. 72, No. 2, 565-572 (2014). MSC: 05C09 05C92 92E10 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, MATCH Commun. Math. Comput. Chem. 72, No. 2, 565--572 (2014; Zbl 1464.05061)
Cvetković, Dragoš Complexity indices for the traveling salesman problem and data mining. (English) Zbl 1291.90199 Trans. Comb. 1, No. 1, 35-43 (2012). MSC: 90C27 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, Trans. Comb. 1, No. 1, 35--43 (2012; Zbl 1291.90199)
Cvetković, Dragoš Spectral recognition of graphs. (English) Zbl 1289.05275 Yugosl. J. Oper. Res. 22, No. 2, 145-161 (2012). MSC: 05C50 68M11 68R10 68T05 PDFBibTeX XMLCite \textit{D. Cvetković}, Yugosl. J. Oper. Res. 22, No. 2, 145--161 (2012; Zbl 1289.05275) Full Text: DOI
Cvetković, Dragoš Applications of graph spectra: an introduction to the literature. (English) Zbl 1289.05276 Cvetković, Dragoš (ed.) et al., Selected topics on applications of graph spectra. Beograd: Matematički Institut SANU (ISBN 978-86-80593-44-9/pbk). Zbornik Radova (Beograd) 14(22), 9-34 (2011). MSC: 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, Zb. Rad. (Beogr.) 14, 9--34 (2011; Zbl 1289.05276)
Cvetković, Dragoš Applications of graph spectra: an introduction to the literature. (English) Zbl 1265.05002 Cvetković, Dragoš (ed.) et al., Applications of graph spectra. Beograd: Matematički Institut SANU (ISBN 978-86-80593-41-8/pbk). Zbornik Radova (Beograd) 13(21), 7-31 (2009). Reviewer: Slobodan Simić (Beograd) MSC: 05-02 05C50 05C90 01A90 PDFBibTeX XMLCite \textit{D. Cvetković}, Zb. Rad. (Beogr.) 13, 7--31 (2009; Zbl 1265.05002)
Cvetković, D. New theorems for signless Laplacian eigenvalues. (English) Zbl 1199.05212 Bull., Cl. Sci. Math. Nat., Sci. Math. 137, No. 33, 131-146 (2008). Reviewer: Slobodan Simić (Beograd) MSC: 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, Bull., Cl. Sci. Math. Nat., Sci. Math. 137, No. 33, 131--146 (2008; Zbl 1199.05212) Full Text: EuDML
Cvetković, D. Signless Laplacians and line graphs. (English) Zbl 1119.05066 Bull., Cl. Sci. Math. Nat., Sci. Math. 131, No. 30, 85-92 (2005). Reviewer: Mirko Lepović (Kragujevac) MSC: 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, Bull., Cl. Sci. Math. Nat., Sci. Math. 131, No. 30, 85--92 (2005; Zbl 1119.05066) Full Text: DOI EuDML
Cvetković, Dragoš Graphs with least eigenvalue \(-2\); the eigenspace of the eigenvalue \(-2\). (English) Zbl 1124.05061 Rend. Semin. Mat. Messina, Ser. II 9(25)(2003), 63-86 (2004). MSC: 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, Rend. Semin. Mat. Messina, Ser. II 9(25), 63--86 (2004; Zbl 1124.05061)
Cvetković, Dragoš Notes on maximal exceptional graphs. (English) Zbl 1089.05043 Publ. Elektroteh. Fak., Univ. Beogr., Ser. Mat. 15, 104-108 (2004). Reviewer: Mirko Lepović (Kragujevac) MSC: 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, Publ. Elektroteh. Fak., Univ. Beogr., Ser. Mat. 15, 104--108 (2004; Zbl 1089.05043)
Cvetković, Dragoš Graphs with least eigenvalue \(-2\); a historical survey and recent developments in maximal exceptional graphs. (English) Zbl 1012.05113 Linear Algebra Appl. 356, No. 1-3, 189-210 (2002). Reviewer: Dieter Rautenbach (Aachen) MSC: 05C50 05C75 PDFBibTeX XMLCite \textit{D. Cvetković}, Linear Algebra Appl. 356, No. 1--3, 189--210 (2002; Zbl 1012.05113) Full Text: DOI
Cvetković, Dragoš Characterizing properties of some graph invariants related to electron charges in the Hückel molecular orbital theory. (English) Zbl 0968.05055 Hansen, Pierre (ed.) et al., Discrete mathematical chemistry. Proceedings of the DIMACS workshop, Rutgers University, New Brunswick, NJ, USA, March 23-24, 1998. Providence, RI: American Mathematical Society (AMS). DIMACS, Ser. Discrete Math. Theor. Comput. Sci. 51, 79-84 (2000). Reviewer: Ko-Wei Lih (Nankang) MSC: 05C50 05C75 PDFBibTeX XMLCite \textit{D. Cvetković}, DIMACS, Ser. Discrete Math. Theor. Comput. Sci. 51, 79--84 (2000; Zbl 0968.05055)
Cvetković, Dragoš On the reconstruction of the characteristic polynomial of a graph. (English) Zbl 0942.05046 Discrete Math. 212, No. 1-2, 45-52 (2000). Reviewer: K.R.Parthasarathy (Narayanapuram) MSC: 05C60 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, Discrete Math. 212, No. 1--2, 45--52 (2000; Zbl 0942.05046) Full Text: DOI
Cvetković, D. On the 2-sum of three graphs variations on the graph product disconnectedness theme. (English) Zbl 1008.05091 Bull., Cl. Sci. Math. Nat., Sci. Math. 118, No. 24, 107-117 (1999). Reviewer: Vojislav Petrović (Novi Sad) MSC: 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, Bull., Cl. Sci. Math. Nat., Sci. Math. 118, No. 24, 107--117 (1999; Zbl 1008.05091)
Cvetković, Dragoš Spanning trees in the theory of graph spectra. (English) Zbl 0942.05015 Kočinac, Ljubiša D., Proceedings of the II mathematical conference in Priština, Yugoslavia, September 25-28, 1996. Priština: Univ. of Priština, Faculty of Sciences. 1-10 (1997). Reviewer: Slobodan Simić (Beograd) MSC: 05C05 05C30 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, in: Proceedings of the II mathematical conference in Priština, Yugoslavia, September 25--28, 1996. Priština: Univ. of Priština, Faculty of Sciences. 1--10 (1997; Zbl 0942.05015)
Cvetković, Dragoš A graph theoretical procedure for clustering binary vectors. (English) Zbl 0932.68064 Ars Comb. 46, 267-276 (1997). Reviewer: Pavel Valtr (Praha) MSC: 68Q65 PDFBibTeX XMLCite \textit{D. Cvetković}, Ars Comb. 46, 267--276 (1997; Zbl 0932.68064)
Cvetković, Dragoš Some supplements to the tables of graph-spectra. (English) Zbl 0942.05035 Publ. Elektroteh. Fak., Univ. Beogr., Ser. Mat. 7, 45-54 (1996). Reviewer: Slobodan Simić (Beograd) MSC: 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, Publ. Elektroteh. Fak., Univ. Beogr., Ser. Mat. 7, 45--54 (1996; Zbl 0942.05035)
Cvetković, Dragoš Star partitions and the graph isomorphism problem. (English) Zbl 0831.05043 Linear Multilinear Algebra 39, No. 1-2, 109-132 (1995). MSC: 05C50 05C60 05E30 68R10 PDFBibTeX XMLCite \textit{D. Cvetković}, Linear Multilinear Algebra 39, No. 1--2, 109--132 (1995; Zbl 0831.05043) Full Text: DOI
Cvetković, Dragoš Graph theoretical procedures in clustering discrete data. (English) Zbl 0767.62045 Publ. Elektroteh. Fak., Univ. Beogr., Ser. Mat. 3, 21-26 (1992). MSC: 62H30 05C90 05C85 PDFBibTeX XMLCite \textit{D. Cvetković}, Publ. Elektroteh. Fak., Univ. Beogr., Ser. Mat. 3, 21--26 (1992; Zbl 0767.62045)
Cvetković, D. Dobrivoje Mihailović (28 August 1909 - 11 January 1987). (Serbo-Croatian. English summary) Zbl 0744.01012 Publ. Elektroteh. Fak., Univ. Beogr., Ser. Mat. 2, 100-101 (1991). MSC: 01A70 01A60 PDFBibTeX XMLCite \textit{D. Cvetković}, Publ. Elektroteh. Fak., Univ. Beogr., Ser. Mat. 2, 100--101 (1991; Zbl 0744.01012)
Cvetković, Dragoš M. Some comments on the eigenspaces of graphs. (English) Zbl 0761.05069 Publ. Inst. Math., Nouv. Sér. 50(64), 24-32 (1991). MSC: 05C50 05C60 PDFBibTeX XMLCite \textit{D. M. Cvetković}, Publ. Inst. Math., Nouv. Sér. 50(64), 24--32 (1991; Zbl 0761.05069)
Cvetković, Dragoš Some possibilities of constructing graphs with given eigenvalues and angles. (English) Zbl 0726.05048 Ars Comb. 29A, 179-187 (1990). Reviewer: P.Jaillet (Austin) MSC: 05C50 PDFBibTeX XMLCite \textit{D. Cvetković}, Ars Comb. 29A, 179--187 (1990; Zbl 0726.05048)
Cvetkovic, Dragoš M. Some results on graph angles. (English) Zbl 0714.05042 Rostocker Math. Kolloq. 39, 74-88 (1990). Reviewer: C.R.J.Clapham MSC: 05C50 05C60 PDFBibTeX XMLCite \textit{D. M. Cvetkovic}, Rostocker Math. Kolloq. 39, 74--88 (1990; Zbl 0714.05042)
Cvetković, Dragoš M. Some graph invariants based in the eigenvectors of the adjacency matrix. (English) Zbl 0696.05036 Graph theory, Proc. 8th Yugosl. Semin., Novi Sad/Yugosl. 1987, 31-42 (1989). Reviewer: A.Torgašev MSC: 05C50 PDFBibTeX XML
Cvetković, Dragoš M. Theory of graph spectra - a theory in which mathematics and computer science are interconnected in a special way. (Serbo-Croatian) Zbl 0721.05045 Glas 353, Od. Prir.-Mat. Nauka, 52, 161-171 (1988). MSC: 05C50 PDFBibTeX XML
Cvetković, Dragoš Constructing trees with given eigenvalues and angles. (English) Zbl 0679.05053 Linear Algebra Appl. 105, 1-8 (1988). Reviewer: A.Torgašev MSC: 05C50 05C05 05C60 PDFBibTeX XMLCite \textit{D. Cvetković}, Linear Algebra Appl. 105, 1--8 (1988; Zbl 0679.05053) Full Text: DOI
Cvetković, D. Discussing graph theory with a computer. VI: Theorems proved with the aid of the computer. (English) Zbl 0662.05058 Bull., Cl. Sci. Math. Nat., Sci. Math. 16, 51-70 (1988). Reviewer: H.N.V.Temperley MSC: 05C99 05-04 68T15 PDFBibTeX XMLCite \textit{D. Cvetković}, Bull., Cl. Sci. Math. Nat., Sci. Math. 16, 51--70 (1988; Zbl 0662.05058)
Cvetković, Dragoš M. Further experiences in computer aided research in graph theory. (English) Zbl 0593.05001 Graphs, hypergraphs and applications, Proc. Conf. Graph Theory, Eyba/GDR 1984, Teubner-Texte Math. 73, 27-30 (1985). Reviewer: H.Kröger MSC: 05-04 05Cxx 68R10 PDFBibTeX XML
Cvetković, Dragoš M. Discussing graph theory with a computer. IV: Knowledge organization and examples of theorem proving. (English) Zbl 0533.05058 Graph theory, Proc. 4th Yugosl. Semin., Novi Sad/Yugosl. 1983, 43-68 (1984). Reviewer: P.van Emde Boas MSC: 05C99 05-04 68T15 PDFBibTeX XML
Cvetković, Dragoš M. Spectral characterizations of line graphs. Variations on the theme. (English) Zbl 0551.05054 Publ. Inst. Math., Nouv. Sér. 34(48), 31-35 (1983). Reviewer: A.Torgašev MSC: 05C50 05C99 PDFBibTeX XMLCite \textit{D. M. Cvetković}, Publ. Inst. Math., Nouv. Sér. 34(48), 31--35 (1983; Zbl 0551.05054) Full Text: EuDML
Cvetkovic, Dragos M. Discussing graph theory with a computer. II: Theorems suggested by the computer. (English) Zbl 0522.05068 Publ. Inst. Math., Nouv. Sér. 33(47), 29-33 (1983). MSC: 05C99 68R10 PDFBibTeX XMLCite \textit{D. M. Cvetkovic}, Publ. Inst. Math., Nouv. Sér. 33(47), 29--33 (1983; Zbl 0522.05068) Full Text: EuDML
Cvetkovic, Dragos On graphs whose second largest eigenvalue does not exceed 1. (English) Zbl 0522.05044 Publ. Inst. Math., Nouv. Sér. 31(45), 15-20 (1982). MSC: 05C50 PDFBibTeX XMLCite \textit{D. Cvetkovic}, Publ. Inst. Math., Nouv. Sér. 31(45), 15--20 (1982; Zbl 0522.05044)
Cvetkovic, D. M. Some possible directions in further investigations of graph spectra. (English) Zbl 0471.05043 Algebraic methods in graph theory, Vol. I, Conf. Szeged 1978, Colloq. Math. Soc. Janos Bolyai 25, 47-67 (1981). MSC: 05C50 05-02 05C75 PDFBibTeX XML
Cvetkovic, D. A project for using computers in further development of graph theory. (English) Zbl 0468.05070 The theory and applications of graphs, 4th int. Conf., Kalamazoo/Mich. 1980, 285-296 (1981). MSC: 05C99 68T15 68T20 PDFBibTeX XML
Cvetkovic, Dragos M. A note on construction of graphs by means of their spectra. (English) Zbl 0478.05015 Publ. Inst. Math., Nouv. Sér. 27(41), 27-30 (1980). MSC: 05B05 05C50 PDFBibTeX XMLCite \textit{D. M. Cvetkovic}, Publ. Inst. Math., Nouv. Sér. 27(41), 27--30 (1980; Zbl 0478.05015) Full Text: EuDML
Cvetkovic, Dragos M. The main part of the spectrum, divisors and switching of graphs. (English) Zbl 0423.05028 Publ. Inst. Math., Nouv. Sér. 23(37), 31-38 (1978). MSC: 05C50 PDFBibTeX XMLCite \textit{D. M. Cvetkovic}, Publ. Inst. Math., Nouv. Sér. 23(37), 31--38 (1978; Zbl 0423.05028) Full Text: EuDML
Cvetkovic, Dragos M. Some topics from the theory of graph spectra. (English) Zbl 0404.05044 Ber. Math.-Stat. Sekt. Forschungszent. Graz 101, 5 P. (1978). MSC: 05C50 PDFBibTeX XML
Cvetkovic, Dragos M. The determinant concept defined by means of graph theory. (English) Zbl 0355.15010 Mat. Vesn., N. Ser. 12(27), 333-336 (1975). MSC: 15A15 05C20 PDFBibTeX XMLCite \textit{D. M. Cvetkovic}, Mat. Vesn., N. Ser. 12(27), 333--336 (1975; Zbl 0355.15010)
Cvetkovic, Dragos Spectra of graphs formed by some unary operations. (English) Zbl 0337.05140 Publ. Inst. Math., Nouv. Sér. 19(33), 37-41 (1975). MSC: 05C99 05B05 PDFBibTeX XMLCite \textit{D. Cvetkovic}, Publ. Inst. Math., Nouv. Sér. 19(33), 37--41 (1975; Zbl 0337.05140) Full Text: EuDML
Cvetkovic, Dragos M. Cubic integral graphs. (English) Zbl 0315.05125 Publ. Fac. Electrotech. Univ. Belgrade, Ser. Math. Phys. 498-541, 107-113 (1975). MSC: 05C99 05B20 15A18 PDFBibTeX XMLCite \textit{D. M. Cvetkovic}, Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 498--541, 107--113 (1975; Zbl 0315.05125)
Cvetkovic, Dragos M. Inequalities obtaied on the basis of the spectrumof the graph. (English) Zbl 0288.05107 Stud. Sci. Math. Hung. 8(1973), 433-436 (1974). MSC: 05C15 05B20 05C35 PDFBibTeX XMLCite \textit{D. M. Cvetkovic}, Stud. Sci. Math. Hung. 8, 433--436 (1974; Zbl 0288.05107)
Cvetkovic, D. M. Über die Zerlegung eines Graphen in ein Produkt von Graphen. (German) Zbl 0281.05114 18. internat. wiss. Kolloqu., Ilmenau 2, 57-58 (1973). MSC: 05C99 PDFBibTeX XML
Cvetković, Dragoš M. Spectrum of the total graph of a graph. (English) Zbl 0274.05118 Publ. Inst. Math., Nouv. Sér. 16(30), 49-52 (1973). MSC: 05C99 05B20 PDFBibTeX XMLCite \textit{D. M. Cvetković}, Publ. Inst. Math., Nouv. Sér. 16(30), 49--52 (1973; Zbl 0274.05118) Full Text: EuDML
Cvetkovic, Dragos M. On a graph theory problem of M. Koman. (English) Zbl 0262.05134 Čas. Pěst. Mat. 98, 233-236 (1973). MSC: 05C99 PDFBibTeX XMLCite \textit{D. M. Cvetkovic}, Čas. Pěstování Mat. 98, 233--236 (1973; Zbl 0262.05134) Full Text: EuDML
Cvetković, Dragoš M. Chromatic number and the spectrum of a graph. (English) Zbl 0271.05111 Publ. Inst. Math., Nouv. Sér. 14(28), 25-38 (1972). MSC: 05C15 05C99 05B25 PDFBibTeX XMLCite \textit{D. M. Cvetković}, Publ. Inst. Math., Nouv. Sér. 14(28), 25--38 (1972; Zbl 0271.05111) Full Text: EuDML
Cvetković, Dragoš M. The number of antichains of finite power sets. (English) Zbl 0266.05004 Publ. Inst. Math., Nouv. Sér. 13(27), 5-9 (1972). MSC: 05A15 03E05 PDFBibTeX XMLCite \textit{D. M. Cvetković}, Publ. Inst. Math., Nouv. Sér. 13(27), 5--9 (1972; Zbl 0266.05004) Full Text: EuDML
Cvetkovic, Dragoš M. Graphs and their spectra. (English) Zbl 0238.05102 Publ. Fac. Electrotech. Univ. Belgrade, Ser. Math. Phys. 354-356, 1-50 (1971). MSC: 05Cxx 05B20 PDFBibTeX XMLCite \textit{D. M. Cvetkovic}, Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 354--356, 1--50 (1971; Zbl 0238.05102)
Cvetković, Dragoš M. The spectral method for determining the number of trees. (English) Zbl 0221.05054 Publ. Inst. Math., Nouv. Sér. 11(25), 135-141 (1971). MSC: 05C05 05C50 PDFBibTeX XMLCite \textit{D. M. Cvetković}, Publ. Inst. Math., Nouv. Sér. 11(25), 135--141 (1971; Zbl 0221.05054) Full Text: EuDML
Cvetković, Dragoš Some remarks on the problem of \(n\) queens. (English) Zbl 0215.33904 Publ. Fac. Electrotech. Univ. Belgrade, Ser. Math. Phys. 274-301(1969), 100-102 (1970). MSC: 05B99 05C99 PDFBibTeX XMLCite \textit{D. Cvetković}, Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 274--301, 100--102 (1970; Zbl 0215.33904)
Cvetković, Dragoš Transzendente Gleichungen, deren Lösungen durch die inversen Funktionen der Funktion \(e^ x/x\) ausdrückbar sind. (German) Zbl 0214.14803 Publ. Fac. Electrotech. Univ. Belgrade, Ser. Math. Phys. 320-328, 15-26 (1970). MSC: 65H05 65D20 PDFBibTeX XMLCite \textit{D. Cvetković}, Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 320--328, 15--26 (1970; Zbl 0214.14803)
Cvetković, Dragoš Spectrum of the graph of \(n\)-tuples. (English) Zbl 0212.29601 Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 274-301(1969), 91-95 (1970). MSC: 05C99 PDFBibTeX XMLCite \textit{D. Cvetković}, Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 274--301, 91--95 (1970; Zbl 0212.29601)
Cvetković, Dragoš Connectedness of the \(p\)-sum of graphs. (English) Zbl 0212.29502 Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 274-301(1969), 96-99 (1970). MSC: 05C40 PDFBibTeX XMLCite \textit{D. Cvetković}, Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 274--301, 96--99 (1970; Zbl 0212.29502)
Cvetković, Dragoš M. Die Zahl der Wege eines Graphen. (German) Zbl 0211.57202 Glas. Mat., III. Ser. 5(25), 205-210 (1970). MSC: 05C38 PDFBibTeX XMLCite \textit{D. M. Cvetković}, Glas. Mat., III. Ser. 5(25), 205--210 (1970; Zbl 0211.57202)
Cvetković, Dragoš M. The generating function for variations with restrictions and paths of the graph and self-complementary graphs. (English) Zbl 0204.24501 Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 320-328, 27-34 (1970). PDFBibTeX XMLCite \textit{D. M. Cvetković}, Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 320--328, 27--34 (1970; Zbl 0204.24501)
Cvetković, Dragoš M. A note on paths in the p-sum of graphs. (English) Zbl 0203.56703 Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 302-319, 49-51 (1970). PDFBibTeX XMLCite \textit{D. M. Cvetković}, Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 302--319, 49--51 (1970; Zbl 0203.56703)
Cvetković, Dragoš M. New characterizations of the cubic lattice graph. (English) Zbl 0202.55704 Publ. Inst. Math., Nouv. Sér. 10(24), 195-198 (1970). PDFBibTeX XMLCite \textit{D. M. Cvetković}, Publ. Inst. Math., Nouv. Sér. 10(24), 195--198 (1970; Zbl 0202.55704) Full Text: EuDML
Cvetkovic, Dragoš Über ein Problem von Erdős. (German) Zbl 0182.26701 Publ. Fac. Electrotech. Univ. Belgrade, Ser. Math. Phys. 247-273, 143-147 (1969). PDFBibTeX XMLCite \textit{D. Cvetkovic}, Publ. Fac. Électrotech. Univ. Belgrade, Sér. Math. Phys. 247--273, 143--147 (1969; Zbl 0182.26701)