This is info from my Links Page on Ribbon Devices.
Bronze Star
Silver Star
The bronze star represents participation in campaigns or operations, multiple qualifications, or an additional award to any of the various ribbons on which it is authorized. The silver star is worn in the same manner as the bronze star, but each silver star is worn in lieu of five bronze service stars.
Silver/Bronze Stars
Bronze Oak Leaf Cluster
When worn together on a single ribbon, the silver star(s) will be worn to the wearer's right of any bronze star(s). The bronze oak leaf cluster represents second and subsequent entitlements of awards.
Silver Oak Leaf Cluster
Silver/Bronze Oak Leaf Clusters
The silver oak leaf cluster represents sixth, 11th, etc., entitlements or in lieu of five bronze oak leaf clusters. Silver oak leaf clusters are worn to the wearer's right of the bronze oak leaf clusters on the same ribbon.
The Valor Device
Valor Devices and Clusters
The "V" device represents valor and does not denote an additional award. Only one may be worn on any ribbon. The "V" device, when worn on the same ribbon with clusters, is worn to the wearer's right of such clusters.
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This is the ribbon the men got for their service in the ETO. The bronze and silver stars mentioned above would be attached to it. Here is the background for that ribbon and the campaigns and landings associated with it.
For instance my father's ETO ribbon shows a silver star (5 campaigns) with a bronze arrowhead.
A bronze star is worn on the ribbon to indicate participation in designated campaigns. The designated campaigns for the European-African-Middle Eastern Theater are:
Egypt-Libya 11 Jun 42 - 12 Feb 43
Air Offensive, Europe 4 Jul 42 - 5 Jun 44
Algeria-French Morocco 8-11 Nov 42
Tunisia 12 Nov 42 - 13 May 43
Sicily 14 May 43 - 17 Aug 43
Naples-Foggia 18 Aug 43 - 21 Jan 44
Anzio 22 Jan 44 - 24 May 44
Rome-Arno 22 Jan 44 - 9 Sep 44
Normandy 6 Jun 44 - 24 Jul 44
Northern France 25 Jul 44 - 14 Sep 44
Southern France 15 Aug 44 - 14 Sep 44
Northern Apennines 10 Sep 44 - 4 Apr 45
Rhineland 15 Sep 44 - 21 Mar 45
Ardennes-Alsace 16 Dec 44 - 25 Jan 45
Central Europe 22 Mar 45 - 11 May 45
Po Valley 5 Apr 45 - 8 May 45
* Antisubmarine 7 Dec 41 - 2 Sep 45
* Ground Combat 7 Dec 41 - 2 Sep 45
* Air Combat: 7 Dec 41 - 2 Sep 45
* These campaigns are not displayed as streamers on the Army flag.
A bronze arrowhead is worn on the ribbon to indicate participation in a combat parachute jump, combat glider landing, or amphibious assault landing within the EAME Theater.
Proud Daughter of Walter (Monday) Poniedzialek
540th Engineer Combat Regiment, 2833rd Bn, H&S Co, 4th Platoon
There's "No Bridge Too Far"