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| | Memorandum 1763, Abstract (Site not responding. Last check: 2007-09-05) |
 | | In general, the problem of characterizing integral graphs seems to be very difficult. |
 | | Trees present another important family of graphs for which the problem has been considered by Harary (1974), Schwenk (1974, 1979), Watanabe (1979), Li(1987, 1999, 2000, 2002, 2004), Liu(1988), Cao (1988, 1991), Yuan(1998), Híc(1997, 1998, 2003), Wang (1999, 2000, 2002, 2004) and others. |
 | | Integral trees with diameters 4, 5, 6 and 8. |
| www.math.utwente.nl /publicaties/2005/1763abs.html (264 words) |
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