Chen, Baoju; Yu, Simin; Li, David Day-Uei; Lü, Jinhu Cryptanalysis of some self-synchronous chaotic stream ciphers and their improved schemes. (English) Zbl 1467.94033 Int. J. Bifurcation Chaos Appl. Sci. Eng. 31, No. 8, Article ID 2150142, 27 p. (2021). MSC: 94A60 PDFBibTeX XMLCite \textit{B. Chen} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 31, No. 8, Article ID 2150142, 27 p. (2021; Zbl 1467.94033) Full Text: DOI
Hu, Yingchun; Yu, Simin; Zhang, Zeqing On the security analysis of a Hopfield chaotic neural network-based image encryption algorithm. (English) Zbl 1445.94023 Complexity 2020, Article ID 2051653, 10 p. (2020). MSC: 94A60 94A08 PDFBibTeX XMLCite \textit{Y. Hu} et al., Complexity 2020, Article ID 2051653, 10 p. (2020; Zbl 1445.94023) Full Text: DOI
Hu, Yingchun; Yu, Simin; Zhang, Zeqing On the cryptanalysis of a bit-level image chaotic encryption algorithm. (English) Zbl 1459.94116 Math. Probl. Eng. 2020, Article ID 5747082, 15 p. (2020). MSC: 94A60 94A08 PDFBibTeX XMLCite \textit{Y. Hu} et al., Math. Probl. Eng. 2020, Article ID 5747082, 15 p. (2020; Zbl 1459.94116) Full Text: DOI
Chen, Baoju; Yu, Simin; Chen, Ping; Xiao, Liangshan; Lü, Jinhu Design and Virtex-7-based implementation of video chaotic secure communications. (English) Zbl 1457.94109 Int. J. Bifurcation Chaos Appl. Sci. Eng. 30, No. 5, Article ID 2050075, 24 p. (2020). MSC: 94A60 94A05 68P25 68M14 PDFBibTeX XMLCite \textit{B. Chen} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 30, No. 5, Article ID 2050075, 24 p. (2020; Zbl 1457.94109) Full Text: DOI
Xu, Birong; Wang, Guangyi; Iu, Herbert Ho-Ching; Yu, Simin; Yuan, Fang A memristor-meminductor-based chaotic system with abundant dynamical behaviors. (English) Zbl 1437.94110 Nonlinear Dyn. 96, No. 1, 765-788 (2019). MSC: 94C05 70K55 37D45 PDFBibTeX XMLCite \textit{B. Xu} et al., Nonlinear Dyn. 96, No. 1, 765--788 (2019; Zbl 1437.94110) Full Text: DOI
Wang, Xiaoyuan; Yu, Jun; Jin, Chenxi; Iu, Herbert Ho Ching; Yu, Simin Chaotic oscillator based on memcapacitor and meminductor. (English) Zbl 1437.94109 Nonlinear Dyn. 96, No. 1, 161-173 (2019). MSC: 94C05 37D45 PDFBibTeX XMLCite \textit{X. Wang} et al., Nonlinear Dyn. 96, No. 1, 161--173 (2019; Zbl 1437.94109) Full Text: DOI
Ying, Jiajie; Wang, Guangyi; Dong, Yujiao; Yu, Simin Switching characteristics of a locally-active memristor with binary memories. (English) Zbl 1439.34057 Int. J. Bifurcation Chaos Appl. Sci. Eng. 29, No. 11, Article ID 1930030, 21 p. (2019). MSC: 34C60 94C05 34C28 34C05 34D20 37C60 PDFBibTeX XMLCite \textit{J. Ying} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 29, No. 11, Article ID 1930030, 21 p. (2019; Zbl 1439.34057) Full Text: DOI
Zhou, Wei; Wang, Guangyi; Shen, Yiran; Yuan, Fang; Yu, Simin Hidden coexisting attractors in a chaotic system without equilibrium point. (English) Zbl 1401.34022 Int. J. Bifurcation Chaos Appl. Sci. Eng. 28, No. 10, Article ID 1830033, 13 p. (2018). MSC: 34A34 34C05 34D45 34C23 PDFBibTeX XMLCite \textit{W. Zhou} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 28, No. 10, Article ID 1830033, 13 p. (2018; Zbl 1401.34022) Full Text: DOI
Lin, Zhuosheng; Yu, Simin; Feng, Xiutao; Lü, Jinhu Cryptanalysis of a chaotic stream cipher and its improved scheme. (English) Zbl 1393.94917 Int. J. Bifurcation Chaos Appl. Sci. Eng. 28, No. 7, Article ID 1850086, 27 p. (2018). MSC: 94A60 39A10 39A33 PDFBibTeX XMLCite \textit{Z. Lin} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 28, No. 7, Article ID 1850086, 27 p. (2018; Zbl 1393.94917) Full Text: DOI
Wang, Qianxue; Yu, Simin; Guyeux, Christophe Design of digital chaotic systems updated by random iterations. (English) Zbl 1400.37002 SpringerBriefs in Applied Sciences and Technology. Nonlinear Circuits. Cham: Springer (ISBN 978-3-319-73548-1/pbk; 978-3-319-73549-8/ebook). xiii, 110 p. (2018). MSC: 37-02 37D45 37H10 94Cxx 34H10 65P20 65C10 11K45 PDFBibTeX XMLCite \textit{Q. Wang} et al., Design of digital chaotic systems updated by random iterations. Cham: Springer (2018; Zbl 1400.37002) Full Text: DOI
He, Jianbin; Yu, Simin; Lü, Jinhu Constructing higher-dimensional nondegenerate hyperchaotic systems with multiple controllers. (English) Zbl 1373.34071 Int. J. Bifurcation Chaos Appl. Sci. Eng. 27, No. 9, Article ID 1750146, 12 p. (2017). MSC: 34C28 34H05 34D08 PDFBibTeX XMLCite \textit{J. He} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 27, No. 9, Article ID 1750146, 12 p. (2017; Zbl 1373.34071) Full Text: DOI
Lin, Zhuosheng; Yu, Simin; Lü, Jinhu A novel approach for constructing one-way hash function based on a message block controlled 8D hyperchaotic map. (English) Zbl 1370.94528 Int. J. Bifurcation Chaos Appl. Sci. Eng. 27, No. 7, Article ID 1750106, 14 p. (2017). MSC: 94A60 37C05 37D45 PDFBibTeX XMLCite \textit{Z. Lin} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 27, No. 7, Article ID 1750106, 14 p. (2017; Zbl 1370.94528) Full Text: DOI
Qiu, Mo; Yu, Simin; Wen, Yuqiong; Lü, Jinhu; He, Jianbin; Lin, Zhuosheng Design and FPGA implementation of a universal chaotic signal generator based on the verilog HDL fixed-point algorithm and state machine control. (English) Zbl 1360.65030 Int. J. Bifurcation Chaos Appl. Sci. Eng. 27, No. 3, Article ID 1750040, 15 p. (2017). MSC: 65C10 94A60 68P25 37D45 PDFBibTeX XMLCite \textit{M. Qiu} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 27, No. 3, Article ID 1750040, 15 p. (2017; Zbl 1360.65030) Full Text: DOI
Wang, Qianxue; Yu, Simin; Li, Chengqing; Lü, Jinhu; Fang, Xiaole; Guyeux, Christophe; Bahi, Jacques M. Theoretical design and FPGA-based implementation of higher-dimensional digital chaotic systems. (English) Zbl 1469.94118 IEEE Trans. Circuits Syst. I, Regul. Pap. 63, No. 3, 401-412 (2016). MSC: 94A60 PDFBibTeX XMLCite \textit{Q. Wang} et al., IEEE Trans. Circuits Syst. I, Regul. Pap. 63, No. 3, 401--412 (2016; Zbl 1469.94118) Full Text: DOI arXiv
He, Jianbin; Yu, Simin; Cai, Jianping Analysis and design of anti-controlled higher-dimensional hyperchaotic systems via Lyapunov-exponent generating algorithms. (English) Zbl 1463.34233 J. Appl. Anal. Comput. 6, No. 4, 1135-1151 (2016). MSC: 34D08 34H10 34C28 34L15 PDFBibTeX XMLCite \textit{J. He} et al., J. Appl. Anal. Comput. 6, No. 4, 1135--1151 (2016; Zbl 1463.34233) Full Text: DOI
He, Jianbin; Yu, Simin; Cai, Jianping Numerical analysis and improved algorithms for Lyapunov-exponent calculation of discrete-time chaotic systems. (English) Zbl 1354.37081 Int. J. Bifurcation Chaos Appl. Sci. Eng. 26, No. 13, Article ID 1650219, 11 p. (2016). MSC: 37M25 37C05 37D45 PDFBibTeX XMLCite \textit{J. He} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 26, No. 13, Article ID 1650219, 11 p. (2016; Zbl 1354.37081) Full Text: DOI
Han, Chunyan; Yu, Simin; Wang, Guangyi A sinusoidally driven Lorenz system and circuit implementation. (English) Zbl 1394.34125 Math. Probl. Eng. 2015, Article ID 706902, 11 p. (2015). MSC: 34H10 34C28 PDFBibTeX XMLCite \textit{C. Han} et al., Math. Probl. Eng. 2015, Article ID 706902, 11 p. (2015; Zbl 1394.34125) Full Text: DOI
Han, Chunyan; Yu, Simin Modified Logistic map and its dynamic performances. (Chinese. English summary) Zbl 1349.37029 Period. Ocean Univ. China 45, No. 5, 120-125 (2015). MSC: 37D45 94A60 68P25 PDFBibTeX XMLCite \textit{C. Han} and \textit{S. Yu}, Period. Ocean Univ. China 45, No. 5, 120--125 (2015; Zbl 1349.37029) Full Text: DOI
He, Jianbin; Yu, Simin; Cai, Jianping A method for image encryption based on fractional-order hyperchaotic systems. (English) Zbl 1355.68081 J. Appl. Anal. Comput. 5, No. 2, 197-209 (2015). MSC: 68P30 68U10 94A08 34C28 PDFBibTeX XMLCite \textit{J. He} et al., J. Appl. Anal. Comput. 5, No. 2, 197--209 (2015; Zbl 1355.68081)
Wang, Qianxue; Yu, Simin; Guyeux, Christophe; Bahi, Jacques M.; Fang, Xiaole Theoretical design and circuit implementation of integer domain chaotic systems. (English) Zbl 1302.37025 Int. J. Bifurcation Chaos Appl. Sci. Eng. 24, No. 10, Article ID 1450128, 10 p. (2014). MSC: 37D45 94C05 PDFBibTeX XMLCite \textit{Q. Wang} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 24, No. 10, Article ID 1450128, 10 p. (2014; Zbl 1302.37025) Full Text: DOI arXiv
Li, Chunlai; Yu, Simin; Luo, Xiaoshu A ring-scroll Chua system. (English) Zbl 1277.34015 Int. J. Bifurcation Chaos Appl. Sci. Eng. 23, No. 10, Article ID 1350170, 12 p. (2013). MSC: 34A34 34C28 34D45 34C20 37D45 37B10 PDFBibTeX XMLCite \textit{C. Li} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 23, No. 10, Article ID 1350170, 12 p. (2013; Zbl 1277.34015) Full Text: DOI
Zhang, Chaoxia; Yu, Simin; He, Qianhua; Ruan, Jinxin On constructing complex grid multiwing chaotic system by switching control and mirror symmetry conversion. (English) Zbl 1275.34061 Int. J. Bifurcation Chaos Appl. Sci. Eng. 23, No. 7, Article ID 1350115, 14 p. (2013). MSC: 34C28 34C14 34H05 37D45 PDFBibTeX XMLCite \textit{C. Zhang} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 23, No. 7, Article ID 1350115, 14 p. (2013; Zbl 1275.34061) Full Text: DOI
Yu, Simin; Lu, Jinhu; Yu, Xinghuo; Chen, Guanrong Design and implementation of grid multiwing hyperchaotic Lorenz system family via switching control and constructing super-heteroclinic loops. (English) Zbl 1468.93092 IEEE Trans. Circuits Syst. I, Regul. Pap. 59, No. 5, 1015-1028 (2012). MSC: 93C30 34H10 37N35 PDFBibTeX XMLCite \textit{S. Yu} et al., IEEE Trans. Circuits Syst. I, Regul. Pap. 59, No. 5, 1015--1028 (2012; Zbl 1468.93092) Full Text: DOI
Zhang, Chaoxia; Yu, Simin; Chen, Guanrong Design and implementation of compound chaotic attractors. (English) Zbl 1258.34119 Int. J. Bifurcation Chaos Appl. Sci. Eng. 22, No. 5, Paper No. 1250120, 13 p. (2012). MSC: 34C60 37D45 34H10 PDFBibTeX XMLCite \textit{C. Zhang} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 22, No. 5, Paper No. 1250120, 13 p. (2012; Zbl 1258.34119) Full Text: DOI
Xi, Huiling; Yu, Simin; Zhang, Chaoxia; Sun, Youlin Generation and implementation of hyperchaotic Chua system via state feedback control. (English) Zbl 1258.34113 Int. J. Bifurcation Chaos Appl. Sci. Eng. 22, No. 5, Paper No. 1250119, 11 p. (2012). MSC: 34C60 34C28 34C23 PDFBibTeX XMLCite \textit{H. Xi} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 22, No. 5, Paper No. 1250119, 11 p. (2012; Zbl 1258.34113) Full Text: DOI
Tang, Zilong; Zhang, Chaoxia; Yu, Simin Design and circuit implementation of fractional-order multiwing chaotic attractors. (English) Zbl 1258.34019 Int. J. Bifurcation Chaos Appl. Sci. Eng. 22, No. 11, Paper No. 1250269, 10 p. (2012). MSC: 34A08 94C05 34D45 93B52 34C28 37D45 PDFBibTeX XMLCite \textit{Z. Tang} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 22, No. 11, Paper No. 1250269, 10 p. (2012; Zbl 1258.34019) Full Text: DOI
Yu, Simin; Chen, Guanrong Chaotifying continuous-time nonlinear autonomous systems. (English) Zbl 1258.34142 Int. J. Bifurcation Chaos Appl. Sci. Eng. 22, No. 9, Paper No. 1250232, 14 p. (2012). MSC: 34H10 34D08 34C11 PDFBibTeX XMLCite \textit{S. Yu} and \textit{G. Chen}, Int. J. Bifurcation Chaos Appl. Sci. Eng. 22, No. 9, Paper No. 1250232, 14 p. (2012; Zbl 1258.34142) Full Text: DOI arXiv
Li, Chunlai; Yu, Simin A new hyperchaotic system and its adaptive tracking control. (Chinese. English summary) Zbl 1265.93153 Acta Phys. Sin. 61, No. 4, 040504 (2012). MSC: 93C40 37N35 PDFBibTeX XMLCite \textit{C. Li} and \textit{S. Yu}, Acta Phys. Sin. 61, No. 4, 040504 (2012; Zbl 1265.93153)
Yu, Simin; Chen, Guanrong Anti-control of continuous-time dynamical systems. (English) Zbl 1248.93083 Commun. Nonlinear Sci. Numer. Simul. 17, No. 6, 2617-2627 (2012). MSC: 93C15 93C05 34H10 93D30 PDFBibTeX XMLCite \textit{S. Yu} and \textit{G. Chen}, Commun. Nonlinear Sci. Numer. Simul. 17, No. 6, 2617--2627 (2012; Zbl 1248.93083) Full Text: DOI
Zhang, Chao-Xia; Yu, Si-Min; Zhang, Yun Design and realization of multi-wing chaotic attractors via switching control. (English) Zbl 1333.34066 Int. J. Mod. Phys. B 25, No. 16, 2183-2194 (2011). MSC: 34C28 37D45 34H10 34C23 34D08 37C75 PDFBibTeX XMLCite \textit{C.-X. Zhang} et al., Int. J. Mod. Phys. B 25, No. 16, 2183--2194 (2011; Zbl 1333.34066) Full Text: DOI
Chen, Jianjun; Yu, Simin Existence of the heteroclinic orbit in a smooth Chua system. (Chinese. English summary) Zbl 1249.37014 Chin. J. Eng. Math. 28, No. 5, 693-701 (2011). MSC: 37D45 37J45 PDFBibTeX XMLCite \textit{J. Chen} and \textit{S. Yu}, Chin. J. Eng. Math. 28, No. 5, 693--701 (2011; Zbl 1249.37014)
Zhang, Chaoxia; Yu, Simin Generation of grid multi-scroll chaotic attractors via switching piecewise linear controller. (English) Zbl 1237.93092 Phys. Lett., A 374, No. 30, 3029-3037 (2010). MSC: 93C30 37N35 65P20 68U20 PDFBibTeX XMLCite \textit{C. Zhang} and \textit{S. Yu}, Phys. Lett., A 374, No. 30, 3029--3037 (2010; Zbl 1237.93092) Full Text: DOI
Yu, Simin; Tang, Wallace K. S.; Lü, Jinhu; Chen, Guanrong Generating \(2n\)-wing attractors from Lorenz-like systems. (English) Zbl 1210.37028 Int. J. Circuit Theory Appl. 38, No. 3, 243-258 (2010). MSC: 37D45 34H10 PDFBibTeX XMLCite \textit{S. Yu} et al., Int. J. Circuit Theory Appl. 38, No. 3, 243--258 (2010; Zbl 1210.37028) Full Text: DOI
Lü, Jinhu; Yu, Simin Theoretical design and circuit realization of complex multi-scroll chaotic systems. (Chinese. English summary) Zbl 1212.37038 Acta Math. Appl. Sin. 32, No. 6, 997-1007 (2009). MSC: 37D45 94C30 PDFBibTeX XMLCite \textit{J. Lü} and \textit{S. Yu}, Acta Math. Appl. Sin. 32, No. 6, 997--1007 (2009; Zbl 1212.37038)
Chen, Jianjun; Yu, Simin A piecewise-linear Sprott system and its chaos mechanism. (Chinese. English summary) Zbl 1212.37020 Acta Phys. Sin. 58, No. 11, 7525-7531 (2009). MSC: 37D45 37J45 PDFBibTeX XMLCite \textit{J. Chen} and \textit{S. Yu}, Acta Phys. Sin. 58, No. 11, 7525--7531 (2009; Zbl 1212.37020)
Yu, Simin; Tang, Wallace K. S. Tetrapterous butterfly attractors in modified Lorenz systems. (English) Zbl 1198.37062 Chaos Solitons Fractals 41, No. 4, 1740-1749 (2009). MSC: 37D45 PDFBibTeX XMLCite \textit{S. Yu} and \textit{W. K. S. Tang}, Chaos Solitons Fractals 41, No. 4, 1740--1749 (2009; Zbl 1198.37062) Full Text: DOI
Yu, Simin; Tang, Wallace K. S. Generation of \(n\times m\)-scroll attractors in a two-port RCL network with hysteresis circuits. (English) Zbl 1197.94237 Chaos Solitons Fractals 39, No. 2, 821-830 (2009). MSC: 94C99 37D45 PDFBibTeX XMLCite \textit{S. Yu} and \textit{W. K. S. Tang}, Chaos Solitons Fractals 39, No. 2, 821--830 (2009; Zbl 1197.94237) Full Text: DOI
Zhang, Chaoxia; Yu, Simin Generation of grid multi-scroll Chua’s chaotic attractors with combination of hysteresis and step series. (Chinese. English summary) Zbl 1199.37102 Acta Phys. Sin. 58, No. 1, 120-130 (2009). MSC: 37D45 94C05 PDFBibTeX XMLCite \textit{C. Zhang} and \textit{S. Yu}, Acta Phys. Sin. 58, No. 1, 120--130 (2009; Zbl 1199.37102)
Yu, Simin; Yu, Zhiding A novel fifth-order hyperchaotic circuit and its research. (Chinese. English summary) Zbl 1199.37101 Acta Phys. Sin. 57, No. 11, 6859-6867 (2008). MSC: 37D45 94C05 PDFBibTeX XMLCite \textit{S. Yu} and \textit{Z. Yu}, Acta Phys. Sin. 57, No. 11, 6859--6867 (2008; Zbl 1199.37101)
Yu, Simin Fourth-order Colpitts chaotic oscillator. (Chinese. English summary) Zbl 1174.37335 Acta Phys. Sin. 57, No. 6, 3374-3379 (2008). MSC: 37D45 94C05 PDFBibTeX XMLCite \textit{S. Yu}, Acta Phys. Sin. 57, No. 6, 3374--3379 (2008; Zbl 1174.37335)
Yu, Simin; Lü, Jinhu; Chen, Guanrong Theoretical design and circuit implementation of multidirectional multi-torus chaotic attractors. (English) Zbl 1374.94933 IEEE Trans. Circuits Syst. I, Regul. Pap. 54, No. 9, 2087-2098 (2007). MSC: 94C05 37D45 37N35 PDFBibTeX XMLCite \textit{S. Yu} et al., IEEE Trans. Circuits Syst. I, Regul. Pap. 54, No. 9, 2087--2098 (2007; Zbl 1374.94933) Full Text: DOI
Yu, Simin; Lu, Jinhu; Chen, Guanrong Multifolded torus chaotic attractors: Design and implementation. (English) Zbl 1159.37407 Chaos 17, No. 1, 013118, 12 p. (2007). MSC: 37D45 PDFBibTeX XMLCite \textit{S. Yu} et al., Chaos 17, No. 1, 013118, 12 p. (2007; Zbl 1159.37407) Full Text: DOI Link
Yu, Simin; Tang, Wallace K. S.; Chen, G. Generation of \(n\times m\)-scroll attractors under a Chua-circuit framework. (English) Zbl 1149.37304 Int. J. Bifurcation Chaos Appl. Sci. Eng. 17, No. 11, 3951-3964 (2007). MSC: 37C70 94C05 37D45 PDFBibTeX XMLCite \textit{S. Yu} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 17, No. 11, 3951--3964 (2007; Zbl 1149.37304) Full Text: DOI
Yu, Simin; Lü, Jinhu; Chen, Guanrong A module-based and unified approach to chaotic circuit design and its applications. (English) Zbl 1134.94411 Int. J. Bifurcation Chaos Appl. Sci. Eng. 17, No. 5, 1785-1800 (2007). MSC: 94C30 94C05 37D45 PDFBibTeX XMLCite \textit{S. Yu} et al., Int. J. Bifurcation Chaos Appl. Sci. Eng. 17, No. 5, 1785--1800 (2007; Zbl 1134.94411) Full Text: DOI
Yu, Simin; Lü, Jinhu; Tang, Wallace K. S.; Chen, Guanrong A general multiscroll Lorenz system family and its realization via digital signal processors. (English) Zbl 1151.94432 Chaos 16, No. 3, 033126, 10 p. (2006). MSC: 94A12 37D45 PDFBibTeX XMLCite \textit{S. Yu} et al., Chaos 16, No. 3, 033126, 10 p. (2006; Zbl 1151.94432) Full Text: DOI
Yu, Simin; Lü, Jinhu; Leung, Henry; Chen, Guanrong Design and implementation of \(n\)-scroll chaotic attractors from a general jerk circuit. (English) Zbl 1374.94934 IEEE Trans. Circuits Syst. I, Regul. Pap. 52, No. 7, 1459-1476 (2005). MSC: 94C05 37N35 34C28 37D45 PDFBibTeX XMLCite \textit{S. Yu} et al., IEEE Trans. Circuits Syst. I, Regul. Pap. 52, No. 7, 1459--1476 (2005; Zbl 1374.94934) Full Text: DOI
Yu, Simin; Qiu, Shuisheng; Lin, Qinghua New results of study on generating multiple-scroll chaotic attractors. (English) Zbl 1185.37090 Sci. China, Ser. F 46, No. 2, 104-115 (2003). MSC: 37D45 94C05 PDFBibTeX XMLCite \textit{S. Yu} et al., Sci. China, Ser. F 46, No. 2, 104--115 (2003; Zbl 1185.37090)