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Can someone post a link to robert rules? Because it still seems undecided in this thread

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http://www.lasvegasvegas.com/poker/rules.php

JoshuaD was correct. The answer you are seeking is in Chapter 14 :

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5. Multiple all-in wagers, each of an amount too small to qualify as a raise, still act as a raise and reopen the betting if the resulting wager size to a player qualifies as a raise.

Example: Player A bets $100 and Player B raises $100 more, making the total bet $200. If Player C goes all in for less than $300 total (not a full $100 raise), and Player A calls, then Player B has no option to raise again, because he wasn't fully raised. (Player A could have raised, because Player B raised.)

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