Many authors have speculated on various aspects of Leonardo's personality.

The authors speculate about this effect but do nothing to address it.

The authors can only speculate about how the two might be linked.

His year of birth is unknown; several authors have speculated, based on varying access to information.

In a different section of the report, the authors speculate about whether statistics during an academic year generalize to an entire college experience.

A few recent authors speculate that they may have reached the coast of North America.

The authors also speculate that the pressure of working and running a household is great.

Possibly the agency had used him as a source, the authors speculate.

Perhaps the therapists included messages about exercise, the authors speculate.

Various authors have speculated on the identity of the ghost.