For nearly every case where you want to store a relationship between two documents, use manual references. The references are simple to create and your application can resolve references as needed.
As it has been indicated in the mongodb reference document it seems to be more reasonable to use manual linkage / reference rather than using the DBRef like this :
stories : [{ type: Schema.ObjectId, ref: 'Story' }]
Implementing the relations via DBref is quite simple as it seems. Apart from that I could not find a reliable resource on how to implement manual reference most efficiently in a schema. Proposals:
stories : [{ type: Schema.ObjectId}] OR
stories : [{ type: Number] OR
stories : [{ type: String]
How the manual reference should be implemented? It would be much appreciated an example of insertion as well.