I am looking here for any sources that respond to the question given:

Can Frege coherently admit expressions that have a sense but lack a reference?

I am familiar with a lot of the exegetical work on the Fregean sense/reference distinction, but I am interested particularly in this subtopic.

Any suggestions would be very welcome.

Thanks

I am looking here for any sources that respond to the question given:

Can Frege coherently admit expressions that have a sense but lack a reference?

I am familiar with a lot of the exegetical work on the Fregean sense/reference distinction, but I am interested particularly in this subtopic.