Neutral baryonic systems with strangeness

We review the status as regards the existence of three- and four-body bound states made of neutrons and $Lambda$ hyperons. For interesting cases, the coupling to neutral baryonic systems made of charged particles of different strangeness has been addressed. There are strong arguments showing that the $Lambda nn$ system has no bound states. $LambdaLambda nn$ strong stable states are not favored by our current knowledge of the strangeness $-1$ and $-2$ baryon-baryon interactions. However, a possible $Xi^- t$ quasibound state decaying to $LambdaLambda nn$ might exist in nature. Similarly, there is a broad agreement about the nonexistence of $LambdaLambda n$ bound states. However, the coupling to $Xi NN$ states opens the door to a resonance above the $LambdaLambda n$ threshold.