https://www.nextgov.com/cybersecurity/2012/07/five-reasons-why-cybersecurity-tough-nut-crack/56814/?oref=ng-homepage-noscript-river
Five reasons why cybersecurity is a tough nut to crack - Nextgov/FCW
Private ownership is among reasons regulation is difficult.
a tough nut to crackfive reasons
https://www.chinadaily.com.cn/bizchina/2014-12/22/content_19137339.htm
Senior care is a tough nut to crack[1]- Chinadaily.com.cn
Although China is in great need of better care for the aging population, senior care companies in the country, local and foreign, have had a tough time trying...
a tough nut to cracksenior care
https://www.bain.com/insights/business-customer-loyalty-a-tough-nut-to-crack-shanghai-daily/
Business customer loyalty a "tough nut to crack" - Shanghai Daily | Bain & Company
Aug 21, 2018 - Passionate customers who love doing business with you: Imagine what it could mean for your B2B company.
a tough nut to crackbusiness customer