Graphviz reduce height of graph

Question

I have some problems with my graph: I'm trieng to reduce the size of it, so it becomes printable in an efficent space. The source looks like this:

digraph G {
 graph[ratio=0.6];
 SANGEBOT;
 PERSON;
 STUDIENGANG;
 KB;
 KB_MODUL;
 MODUL;
 PRUEFUNG;
 PE;
 SEMESTER;
 HISTORY;
 ETHISTORY;
 LV;
 LV_PE;

 SANGEBOT -> PERSON  [style=bold,label="TABLE_BETREUER"];
 SANGEBOT -> PERSON  [style=bold,label="TABLE_PRUEFER"];
 SANGEBOT -> PERSON  [style=bold,label="TABLE_DOZENT"];
 NEU_LV -> PERSON  [style=bold,label="NEU_DOZENT"];
 NEU_LV -> PERSON  [style=bold,label="NEU_BETREUER"];
 LV -> PERSON  [style=bold,label="TABLE_APARTNER_LV"];
 MODUL -> PERSON  [style=bold,label="TABLE_APARTNER_MODUL"];
 NEU_LV -> PERSON  [style=bold,label="NEU_PRUEFER"];
 HISTORY -> SEMESTER  [style=bold,label="SEMESTER"];
 ETHISTORY -> SEMESTER  [style=bold,label="SEMESTER"];
 NEU_LV -> PERSON  [style=bold,label="APARTNER"];
 NEU_LV -> SEMESTER  [style=bold,label="SEMESTER"];
 NEU_LV -> KB  [style=bold,label="KB1_INF_MSC"];
 NEU_LV -> KB  [style=bold,label="KB2_INF_MSC"];
 NEU_LV -> MODUL  [style=bold,label="MODUL_INF_ALT"];
 NEU_LV -> MODUL  [style=bold,label="MODUL_INF_BSC"];
 NEU_LV -> MODUL  [style=bold,label="MODUL_INF_MSC"];
 NEU_LV -> MODUL  [style=bold,label="MODUL_ET"];
 NEU_LV -> MODUL  [style=bold,label="MODUL_TI_BSC"];
 NEU_LV -> MODUL  [style=bold,label="MODUL_TI_MSC"];
 NEU_LV -> KB  [style=bold,label="KB1_TI_MSC"];
 NEU_LV -> KB  [style=bold,label="KB2_TI_MSC"];
 KB -> STUDIENGANG  [style=bold,label="SG"];
 KB -> SEMESTER  [style=bold,label="GUELTIG_VON"];
 KB -> SEMESTER  [style=bold,label="GUELTIG_BIS"];
 KB_MODUL -> KB  [style=bold,label="KB"];
 KB_MODUL -> MODUL  [style=bold,label="MODUL"];
 KB_MODUL -> SEMESTER  [style=bold,label="GUELTIG_VON"];
 KB_MODUL -> SEMESTER  [style=bold,label="GUELTIG_BIS"];
 LV_PE -> LV  [style=bold,label="LV"];
 LV_PE -> PE  [style=bold,label="PE"];
 LV_PE -> SEMESTER  [style=bold,label="GUELTIG_VON"];
 LV_PE -> SEMESTER  [style=bold,label="GUELTIG_BIS"];
 PRUEFUNG -> MODUL  [style=bold,label="MODUL"];
 PRUEFUNG -> PE  [style=bold,label="PE"];
 PRUEFUNG -> SEMESTER  [style=bold,label="GUELTIG_VON"];
 PRUEFUNG -> SEMESTER  [style=bold,label="GUELTIG_BIS"];
 SANGEBOT -> LV  [style=bold,label="LV"];
 SANGEBOT -> SEMESTER  [style=bold,label="SEMESTER"];
 MODUL -> SEMESTER  [style=bold,label="GUELTIG_VON"];
 MODUL -> SEMESTER  [style=bold,label="GUELTIG_BIS"];
 STUDIENGANG -> SEMESTER  [style=bold,label="GUELTIG_VON"];
 STUDIENGANG -> SEMESTER  [style=bold,label="GUELTIG_BIS"];
 PERSON -> SEMESTER  [style=bold,label="GUELTIG_VON"];
 PERSON -> SEMESTER  [style=bold,label="GUELTIG_BIS"];
 LV -> SEMESTER  [style=bold,label="GUELTIG_VON"];
 LV -> SEMESTER  [style=bold,label="GUELTIG_BIS"];
 PE -> SEMESTER  [style=bold,label="GUELTIG_VON"];
 PE -> SEMESTER  [style=bold,label="GUELTIG_BIS"];
}

And the result looks like this: Result. Does anyone know how to archieve a smaller graph? Thanks for your help!