Dutch Treat - by Ted Diehl-Peshkur – iW Magazine, January 2009. A superb introduction to the Grönefeld Brothers and their GTM-06 watch.

Their Time Has Come - by Robin Swithinbank – QP Magazine, January 2010 – Introduces their 1912 One-Hertz Independent Dead - Seconds wristwatch.

The Taboo Complication - by Ron DeCorte – Watch Around Magazine, Spring/Summer 2011 – Explains their independent dead seconds mechanism.

Gentlemen's Gadgets – The Youngest "most expensive watch of the world" by Grönefeld

AskMen.com – Grönefeld Exclusive Timepieces: One Hertz

A Blog to Read – Grönefeld One hertz 1912 Dead-Beat Seconds Watch

Monochrome Interview – Interview with Tim and Bart grönefeld

AHCI Post – Finishing a Bridge

Monochrome Article – Grönefeld One Hertz – independent deadbeat seconds

Timezone Forum – Grönefeld's newest Creation: the "One Hertz" powered by the G-02 "Independent deat beat seconds" movement

Watchmaker.com – The Grönefeld One Hertz is a Complete DeadBeat

AHCI Post – New Watch – Grönefeld GTM06

Tempus Fugit Watch Interview – A Few Minutes with Bart and Tim Grönefeld