depth of coverage outputs gatk

[m_elena_bioinfo]

Hi to everybody,
I run
> java -jar GenomeAnalysisTK.jar -T DepthOfCoverage -R hg19.fasta -I sample.bam.sorted.bam -L chr22 --minMappingQuality 20 -o coverage.txt

and the script returns me different outputs:

1.sample_cumulative_coverage_counts
2. sample_cumulative_coverage_proportions
3. sample_interval_statistics
4. sample_interval_summary
5. sample_statistics
6. sample_summary

Anyone could explain me these outputs?