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*Burwitz, V., *Reinch, K., *Schwope, A.D., *Hakala, P.J., *Beuermann, K., *Rousseau, Th., *Thomas, H.-C., *Gansicke, B.T., Piirola, V., *Vilhu, O. 1998: A new ROSAT discovered polar near the lower period limit: RXJ1015.5+0904 in Leonis - Astronomy & Astrophysics 331, 262

Chernin, A.D., Valtonen, M.J. 1998: Intermittent chaos in three-body dynamics - New Astronomy Reviews 42, 41-66

Chernin, A.D. 1998: Bubble - bubble collision and merging: computer simulations - In Breidtschwerd M. et al. (eds.) Local Bubble and Beyond. Springer-Verlag, 124-128

*Dolgachev, V.P., *Kalinina, E.P., Chernin, A.D. 1998: Dynamics of interstellar clouds in the Galaxy - Andromeda Nebula system - Astronomical and Astrophysical Transactions 15, 31-36

*Fuchs, B., *Jahreiss, H., Flynn, C. 1998: The contribution of brown dwarfs to the local mass budget of the Galaxy - Astronomy and Astrophysics 339, 405-408

*Gould, A., Flynn, C., *Bahcall, J. N. 1998: Spheroid Luminosity and Mass Functions from Hubble Space Telescope Star Counts - Astrophysical Journal 503, 798

*Hagen-Thorn, V.A., *Marchenko, S.G., Takalo, L.O., Sillanpää, A., Pursimo, T., *Kidger, M., *Gonzales-Perez, J.N. 1998: Analysis of the colour variations of 3C 66A in the optical-IR region during 1993-1995 - In Multifrequency monitoring of blazars, OJ-94 Annual Meeting 1997, Perugia, Italy 8-9 September 1997, Edited by G. Tosti, L. Takalo, Perugia University Observatory Publications, Vol. 3, 17-23

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*Hakala, P.J., *Chaytor, D.H., *Vilhu, O., Piirola, V., *Morris, S.L., *Muhli, P. 1998: Optical and X-ray study of MS1603+2600 - Astronomy & Astrophysics 333, 540

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*Innanen, K., Mikkola, S., *Wiegert, P. 1998: The Earth-Moon system and the dynamical stability of the inner Solar System - Astronomical Journal 166, 2055--2057

*Jimenez, R., Flynn, C., Kotoneva, E. 1998: Hipparcos and the age of the Galactic disc - Monthly Notices of the Royal Astronomical Society 299, 515-519

*Karachentsev, I., *Drozdowsky, I., *Kajsin, S., Takalo, L.O., Heinämäki, P., Valtonen, M. 1998: Revised photometric distances to nearby dwarf galaxies in the IC 342/Maffei complex - Astronomy & Astrophysics 124, 559

Karttunen, H., *Linnaluoto, S. *Manner, O., *Mäkelä, V., *Suhonen, M. (toim.) 1998: Tähdet 1999, Ursa, Helsinki, 144 s.

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Karttunen, H. 1998: Gravitaatiosta graafiseen almakkaan. Kirjassa Haataja, J. (toim.): Alkuräjähdyksestä kännykkään, CSC, 77-87.

Karttunen, H. 1998: Uhka taivaalta. - Tieteessä tapahtuu 7/1998: 13-15.

*Kiseleva, L.G., *Eggleton, P.P., Mikkola, S. 1998: Tidal friction in triple stars - Monthly Notices of Royal Astronomical Society 300, 292-302.

Kotilainen, J.K., *Falomo, R., *Scarpa, R. 1998: Near-infrared imaging of the host galaxies of flat radio spectrum quasars - Astronomy & Astrophysics 332, 503-513

Kotilainen, J.K., *Falomo, R., *Scarpa, R. 1998: The host galaxies of BL Lac objects in the near-infrared - Astronomy & Astrophysics 336, 479-489

Kotilainen, J.K. 1998: Near infrared imaging of the host galaxies of flat spectrum radio quasars - In Extragalactic Astronomy in the Infrared, eds. G.A. Mamon, T.X. Tthuan and J.T.T. Van, Editions Frontiers, Paris, 363-368

Kotilainen, J.K. 1998: Optical colour maps of Seyfert galaxies. II. More Seyfert 2s - Astronomy & Astrophysics Supplement Series 132, 197-210

*Kurtanidze, O.M., *Nikolashvili, M.G., Takalo, L.O. 1998: The activity of BL Lac during the summer 1997 outburst - In Multifrequency monitoring of blazars, OJ-94 Annual Meeting 1997, Perugia, Italy 8-9 September 1997, Edited by G. Tosti, L. Takalo, Perugia University Observatory Publications, Vol. 3, 193-195

*Lähteenmäki A., Valtaoja, E. 1998: Limiting brightness temperature for a synchrotron source. - IAU Colloquium 164, Radio Emission from Galactic and Extragalactic Compact Sources,, eds. J.A. Zensus, G.B. Taylor, J.M. Wrobel, ASP Conference Series Vol. 144, San Francisco, p. 135-136

*Laine, S., Kotilainen, J.K., *Ryder, S.D., Reunanen, J., *Ruiz, M., *Storey, J.W.V. 1998: Near-infrared line imaging of circumnuclear star formation in Seyfert and starburst galaxies - Bulletin of the American Astronomical Society 193, 7601

*Makarova, L. *Karachentsev, I., Takalo, L.O., Heinämäki, P., Valtonen, M.J. 1998: A detailed imaging and distance mesurments for eighteen dwarf irregular galaxies in the Canes Venatici cloud - Astronomy and Astrophysics Supplemet series 128, 459-470.

*McHardy, I.M., *Jones, L.R., *Merrifield, M.R., *Mason, K.O., *Abraham, R.G., *Newsam, A.M., *Dalton, G. B., *Carrera F., *Smith, P.J., *Rowan-Robinson, M., *Wegner, G., Lehto, H.J., *Branduardi-Raymont, G., *Luppino, G.A., *Efstathiou, G., *Ponman, T., *Allen, D., *Quenby, J.J., 1998: The Origin of the Cosmic Soft X-ray Background: Optical Identification of an Extremely Deep Rosat Survey. - Monthly Notices of the Royal Astronomical Society 295: 641-671.

*McHardy, I.M., *Jones, L.R., *Merrifield, M.R., *Mason, K.O., *Newsam, A.M., *Abraham, R.G., *Dalton, G.B., *Carrera, F., *Smith, P.J., *Rowan-Robinson, M., *Wegner, G.A., *Ponman, T.J., Lehto, H.J., *Branduardi-Raymont, G., *Luppino, G.A., *Efstathiou, G., *Allan, D.J., *Quenby, J.J. 1998: The UK ROSAT Deep Survey. - Astronomische Nachrichten 319: 51.

Mikkola, S., *Aarseth S.J. 1998: An efficient integration method for binaries in N-body simulations - New Astronomy 3, 309-320.

Mikkola, S., *Tanikawa, K. 1998: Does Kozai Resonance Drive CH-Cygni? - Astronomical Journal 116, 444-450.

Mikkola, S. 1998: Non-canonical perturbations in symplectic integration - Celestial Mechanics and Dynamical Astronomy 68: 249-255

Nilsson, K., Pursimo, T., Takalo, L.O., Sillanpää, A., *Heidt, J. 1998: Deep Optical Images of 3C 66A - In Multifrequency monitoring of blazars, OJ-94 Annual Meeting 1997, Perugia, Italy 8-9 September 1997, Edited by G. Tosti, L. Takalo, Perugia University Observatory Publications, Vol. 3, 43-48

Nilsson, K. 1998 : Kinematical models of double radio sources and the unified scheme: II. The database, Astronomy and Astrophysics Supplement Series 132:31-37

*Palazzi, E., *Pian, E., *Masetti, N., *Nicastro, L., *Vreeswijk, P., *Galama, T.J., *Groot, P., *Frontera, F., *Della Valle, M., *Lidman, C., *Kouveliotou, C., *Pizzichini, G., *van Paradijs, J., *Pedersen, H., *Mannucci, M., *Di Martino, M., *Amati, L., *Benetti, S., *Castro-Tirado, A.J., *Clasen, J., *Costa, E., *Sal Fiume, D., *Falomo, R., *Feroci, M., *Fynbo, J., *Heise, J., *in' Zand J., *Patat, F., *Piro, L., *Robinson, C., *Tornikoski, M., Valtaoja, E., *Zapatero-Osorio, M.R. 1998: Optical and near-infrared followup observations of GRB980329. - Astronomy and Astrophysics 336, L95-L99

*Paturel, G., *Lanoix, P., Teerikorpi, P., *Theureau, G., *Bottinelli, L., *Gouguenheim, L., *Renaud, N., *Witasse, O. 1998: Hubble constant from sosies galaxies and HIPPARCOS geometrical calibration - Astronomy and Astrophysics 339, 671-677

Pietilä, H. 1998: Possibilities and predictions of the OJ 287 binary black hole model - Astrophysical Journal 508, 669 -675

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Riehokainen, A., *Urpo, S., Valtaoja, E. 1998: Enhanced temperature regions in the polar zones of the Sun. - Astronomy and Astrophysics 333, 741-745

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*Shkuratov, Yu. G., *Kreslavsky, M. A., *Ovcharenko, A. A., *Muinonen, K., *Piironen, J., and Karttunen, H. 1998: Oppozitsionnyij effekt jarkosti kosmitsheskih objektov kak diagnostitsheskij faktor (Summary: Diagnostic sense of opposition effect of solid planetary surfaces). - Kosmitshna nauka i tehnologija 4, 1-6.

Sillanpää, A., Takalo, L.O., *Teräsranta, H., Katajainen, S., Keinänen, P., Koskimies, M., Kotoneva, E., Lainela, M., Nilsson, K., Nurmi, P., Hanski, M., Pietilä, H., Pursimo, T., Rekola, R., Riehokainen, A. 1998: Multifrequency behaviour of TeV blazars Mk421 and Mk501 - In Multifrequency monitoring of blazars, OJ-94 Annual Meeting 1997, Perugia, Italy 8-9 September 1997, Edited by G. Tosti, L. Takalo, Perugia University Observatory Publications, Vol. 3, 150-156

Sillanpää, A., Takalo, L.O., Heinämäki, P., Katajainen, S., Keinänen, P., Koskimies, M., Kotoneva, E., Lainela, M., Nilsson, K., Nurmi, P., Hanski, M., Pietilä, H., Pursimo, T., Rekola, R., Riehokainen, A., *Turner, G.W., *Robertson, J.W., *Honeycut, R.K., *Efimov, Y.S., *Shakhovskoy, N., *Tosti, G., *Fiorucci, M., *Luciani, M., *Rizzi, N., *Villata, M., *Raiteri, C.M., *De Francesco, G., *Lanteri, L., *Chiaberge, M., *Peila, A., *Sorbito, G., *Cavallone, M., *Massaro, E., *Maesano, M., *Montagni, F., *Nesci, R., *Boltwood, D., *Dultzin-Hacyan, D., *Benitez, E., *Heidt, J. 1998: Multifrequency observations of OJ 287 and 3C 66A - In Multifrequency monitoring of blazars, OJ-94 Annual Meeting 1997, Perugia, Italy 8-9 September 1997, Edited by G. Tosti, L. Takalo, Perugia University Observatory Publications, Vol. 3, 5-10

Takalo, L.O., Sillanpää, A., Hanski, M., Heinämäki, P., Katajainen, S., Keinänen, P., Koskimies, M., Kotoneva, E., Lainela, M., Nilsson, K., Nurmi, P., Pietilä, H., Pursimo, T., Rekola, R., Riehokainen, A. 1998: BL Lac observed at Tuorla during summer 1997 - In Multifrequency monitoring of blazars, OJ-94 Annual Meeting 1997, Perugia, Italy 8-9 September 1997, Edited by G. Tosti, L. Takalo, Perugia University Observatory Publications, Vol. 3, 200-203

Takalo, L.O., Sillanpää, A., Hanski, M., Heinämäki, P., Katajainen, S., Keinänen, P., Koskimies, M., Kotoneva, E., Lainela, M., Nilsson, K., Nurmi, P., Pietilä, H., Pursimo, T., Rekola, R., Riehokainen, A. 1998: Optical quasar monitoring program at Tuorla Observatory - In Multifrequency monitoring of blazars, OJ-94 Annual Meeting 1997, Perugia, Italy 8-9 September 1997, Edited by G. Tosti, L. Takalo, Perugia University Observatory Publications, Vol. 3, 97-102

Takalo, L.O., Sillanpää, A., Valtaoja, E., Katajainen, S., Nilsson, K., Pursimo, T., Heinämäki, P., *Villata, M., *Raiteri, C.M., *Ghisellini, G., *de Francesco, G., *Lanteri, L., *Chiaberge, M., *Peila, A., *Boltwood, P., *Tosti, G., *Fiorucci, M., *Teräsranta, H., *Tornikoski, M. 1998: Monitoring of AO 0235+164 during a faint state - Astronomy and Astrophysics Supplement Series 129, 577-582

Teerikorpi P, Hanski M, *Theureau G., *Baryshev Yu, *Paturel G, *Bottinelli L, *Gouguenheim L. 1998: The radial space distribution of KLUN-galaxies up to 200 Mpc: incompleteness or evidence for the behaviour predicted by fractal dimension ÷ 2? - Astronomy & Astrophysics 334, 395-403

Teerikorpi P. 1998: Cosmological Malmquist bias in the Hubble diagram at high redshifts - Astronomy and Astrophysics 339, 647-657

*Teräsranta, H., *Tornikoski, M., *Mujunen, A., *Karlamaa, K., *Valtonen, T., *Henelius, N., *Urpo, S., Lainela, M., Pursimo, T., Nilsson, K., Wiren, S., *Lähteenmäki, A., Korpi, M., Rekola, R., Heinämäki, P., Hanski, M., Nurmi, P., Kokkonen, K., Keinänen, P., Joutsamo, O., Oksanen, J., Pietilä, H., Valtaoja, E., Valtonen, M. & *K"n"nen, P. 1998: Fifteen years monitoring of extragalactic radio sources at 22, 37 and 87 GHz. - Astronomy and Astrophysics Supplement Series 132, 305-331

*Theureau G, *Bottinelli L, *Coudreau-Durand N, *Gouguenheim L, *Hallet N, *Loulergue M, *Paturel G, *Teerikorpi P. 1998: Observational data for the kinematics of the local universe VI. 21-cm line measurements - Astronomy & Astrophysics Supplement Series 130, 333-339

*Tornikoski, M., *Teräsranta, H., Valtaoja, E. 1998: The radio behaviour of BL Lacertae during the 1997 optical outburst - In Multifrequency monitoring of blazars, OJ-94 Annual Meeting 1997, Perugia, Italy 8-9 September 1997, Edited by G. Tosti, L. Takalo, Perugia University Observatory Publications, Vol. 3, 206-207

*Tornikoski, M., Valtaoja, E. 1998: The radio vs. optical behaviour in OJ 287 - In Multifrequency monitoring of blazars, OJ-94 Annual Meeting 1997, Perugia, Italy 8-9 September 1997, Edited by G. Tosti, L. Takalo, Perugia University Observatory Publications, Vol. 3, 56-61

*Tosti, G., *Fiorucci, M., *Luciani, M., *Efimov, Yu.S., *Shakhovskoy, N.M., Valtaoja, E., *Teräsranta, H., Sillanpää, A., Takalo, L.O., *Villata, M., *Raiteri, C.M., *De Francesco, G., *Sobrito, G. 1998: Radio, optical and photopolarimetric observations of Markarian 421 around the great 1996-97 outburst. - Astronomy and Astrophysics 339, 41-51

*Tosti, G., *Fiorucci, M., *Rizzi, N., *Luciani, M., *Villata, M., *Raiteri, C.M., *Ghisellini, G., *De Francesco, G., *Lanteri, L., *Chiaberge, M., *Peila, A., *Cavallone, M., *Sobrito, G., *Massaro, E., *Nesci, N., *Maesano, M., *Montagni, F., Takalo, L.O., Sillanpää, A., Katajainen, S., Heinämäki, P., Nilsson, K., Pursimo, T. 1998: BVRI monitoring of ON 231 during the great outburst in 1994-1997 - Astronomy and Astrophysics Supplemet series 130, 109-115,

*Tosti, G., Takalo, L.O. (editors) 1998: OJ-94 Annual Meeting 1997. Multifrequency monitoring of Blazars - Publicazioni Osservatorio Astronomico Universita di Perugia 3

Valtaoja, E. 1998: Mustat aukot - Tähdet ja avaruus 3/98 p. 13-16

Valtaoja, E. 1998: OJ 287: no VLBI observations, no understanding of radio and optical variations? Multifrequency Monitoring of Blazars, eds. G. Tosti and L. Takalo - Perugia University Observatory Publications, Vol. 3, p. 62-67

Valtaoja, E. 1998: Oxfordin moottorisahamurhat - eli mitä todellisuuden rakenteesta voidaan tietää. - Tieteessä tapahtuu 2/1998, p. 42-45

Valtaoja, E. 1998: Structure and properties of AGN cores from VLBI and total flux density variations. IAU Colloquium 164, Radio Emission from Galactic and Extragalactic Compact Sources,, eds. J.A. Zensus, G.B. Taylor, J.M. Wrobel - ASP Conference Series Vol. 144, San Francisco, p. 35-36

Valtaoja, E. 1998: Tervetuloa multiversumiin! - Tiede 2000 3/98 p. 4-8

Valtonen, M.J., Zheng, J.Q., Mikkola, S., Nurmi, P., *Rickman, H. 1998: Monte Carlo simulations of Comet Capture from the Oort Cloud - Celestial Mechanics and Dynamical Astronomy 69: 89-102.

Valtonen, M.J. 1998: Mass Ratios in Multiple Star Systems - Astronomy and Astrophysics 334, 169 - 172

*Villata, M., *Raiteri, C., Sillanpää, A., Takalo, L.O. 1998: A beaming model for the OJ 287 periodic optical outbursts - Monthly Notices of the Royal Astronomical Society 293, L13

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*Whitmire, D., Mathese, J., Griswell, L., Mikkola, S. 1998: Habitable Planet Formation in Binary Star Systems - ICARUS, 132, 196-203.

*Wiegert, P.A., *Innanen, K.A., Mikkola, S. 1998: The orbital evolution of near-Earth asteroid 3753 - Astronomical Journal 115, 2604-2613.

*Wiik, K., Valtaoja, E. 1998: Three epoch VLBI observations of a sample of 15 AGN at 22 GHz: Comparison of total flux and VLBI properties. IAU Colloquium 164, Radio Emission from Galactic and Extragalactic Compact Sources,, eds. J.A. Zensus, G.B. Taylor, J.M. Wrobel - ASP Conference Series Vol. 144, San Francisco, p. 151-152