The phrase "a combination of mail" is correct and usable in written English.
It can be used when referring to a mix or blend of different types of mail, such as physical letters and electronic messages.
Example: "The project requires a combination of mail, including both traditional letters and emails, to reach all stakeholders effectively."
Alternatives: "a mix of mail" or "a blend of mail".
The mode of data collection was a combination of mailed and emailed questionnaires, depending on the patients' preference.
A combination of mailed questionnaires and telephone interviews is being used to maximise disclosure of health problems during pregnancy and follow-up.
Results indicate that a combination of mailed interventions together (CRUK endorsement flyer and kit enhancement pack) was associated with an increase in uptake that was small but significantly higher than for controls, among adults invited for bowel cancer screening across London.
We've been able to find these customers using a combination of direct mail catalogs and direct sales to distributors.
He got in touch with Louise Weiss and Robert Posey, two of the reunion's organizers who still live in Westchester, and, through a combination of e-mail and plain old-fashioned phone calls, got enough photographs and mini-bios to start an online yearbook.
The site includes Web links and contact information for each theater, and by a combination of e-mail messages and faxes (in our ludicrously rudimentary Italian, whose solecisms seem to have been forgiven and whose thrust -- "Sell me tickets, please" -- was apparently understood), we were able to buy seats for all three operas.
After all, there's now a large, public company with a big track record in handling large-scale campaigns offering a combination of e-mail marketing, online survey and event marketing tools all-in-one.
Navigation varies with respect to intervention dose, frequency of contact, and duration; however, most interventions are delivered primarily via telephone or a combination of telephone and mail (31).
The website has managed to drop the price of the Palm Pre down to only $99 through a combination of instant and mail-in rebates.
